A good summary of the NH law is at Citizens Court. Unfortunately, this law, like most laws, is open to interpretation. Although the Citizens Court article says, “[t]he law is specifically concerned with lewd actions that are intentionally offensive,” the text of the law seems to apply to simple nudity in some cases.
We’ve already experienced partial legalization. For example, men had to fight for the right to be shirtless in the 30’s, there is a famous picture of a police officer measuring the length of a swimsuit on a women, and more recently (1999), breast feeding was legalized in NH. All of these incremental changes were initially met with moral alarmism, but we think everyone can agree that these were positive changes.
There was a bill to legalize toplessness in NH. It was defeated, but it had a lot of support, united our community and allies, raised awareness, and revealed the statists!
tl;dr: Not getting dressed is not an initiation of force. As for public nudity, the best solution is to privatize the space, and the worst solution is to initiate force to stop peaceful behavior.
The preamble of the Libertarian Party platform begins:
We seek a world of liberty: a world in which all individuals … are not forced to sacrifice their values for the benefit of others … we defend each person’s right to engage in any activity that is peaceful and honest, and welcome the diversity that freedom brings 
Libertarians fundamentally believe that you own your own body, and you can do anything you wish with it, as long as what you do is not a direct initiation of force. There are various justifications for this non-aggression principle, but principled libertarians take it very seriously, and it is the reason we think things like taxation and slavery is wrong, and support other rights - like free speech, right to bear arms, free trade, and right to experiment with drugs.
Because of this, libertarians are strong supporters of the freedom of expression. A plank in the Libertarian Party of California platform, as adopted 16 May 2021, delineated the position. It is reproduced here in its entirety, to see how the issue fits in with other libertarian positions.
Individuals have the right to hold their own ideas and opinions, and to express and receive ideas, opinions, and information. Government should not – itself or in cooperation with private entities – compel, censor, or regulate expression, or any methods of communication, including in cases where the public may deem such expression as offensive or obscene.
Specifically, we support:
A. Open debate or expression in a “marketplace of ideas”.
B. The ability of private individuals, groups, and companies to prohibit subjectively offensive material on their property, physical or virtual.
C. The deregulation of television, radio, cable, the internet, blockchain, and all other forms of communication.
D. The right of suspects, defendants, and convicted criminals to open criminal proceedings and communication with the media.
In addition, we oppose:
A. The use of political violence and vandalism, including at protests.
B. Interference or intimidation by government in news media, such as by prosecuting whistleblowers, suing journalists, discrediting the media, or raiding newsrooms.
C. Speech codes, dress codes, clothing mandates, and other policies that restrict discussion of ideas in public spaces or at public colleges and universities, or limit such expression to “free speech zones” or other designated areas.
D. Restrictions of the right of adults to make, distribute, possess or view sexually explicit material.
E. Bans on flag burning and mandates to salute a flag.
F. Mandates to conceal beliefs or profess any religion.
G. Requirements that property owners post material or allow others to use their property as a venue for expressing views.
H. Regulations that limit the content or financial support of political campaigns.
Libertarians support the right to non-aggressive things, it doesn’t mean they necessarily support the non-aggressive thing itself. A libertarian may not support drug use or nudity, but they will never initiate force to stop it.
It is possible that, in the ideal realization of a libertarian society known as Ancapistan, nudity may be banned on all private property. Yes, anything - including guns and books, may be de facto banned in Ancapistan. However, given how severely and arbitrarily governments treat simple nudity, we believe that a free society will be more tolerant towards simple nudity than the United States currently is.
There are several reasons why body freedom activism is important.
- Government clothing mandates are violation of our self-ownership. One of the first things that happens every morning is that we are compelled to dress, for the sole purpose of making other people comfortable, at the expense of our own comfort and happiness. If we don’t comply, we face life-ending punishments. All of us would find it objectionable that women in some countries must cover themselves head-to-toe, or be subject to corporeal punishment or rape. Sadly, we’re not that different here in the US. Recently in Utah, a women was topless at her own home while installing drywall , and she was charged with lewd conduct.
- We heard during the pandemic, “if the government can force people to wear clothes, then they can definitely force people to wear masks for health reasons!” Taking a soft stance on one issue can result in losing ground on other issues.
- If we want to attract libertarians from around the world, then NH needs to be more free than other places. Unfortunately, Manchester, NH bans toga parties, while neighboring Vermont doesn’t have a State law banning nudity at all.
- There is no evidence that simple nudity is harmful, and there’s plenty of evidence to the contrary. It’s considered enriching in art and health science textbooks. Practicing nudism is fun, and being comfortable with your body is healthy.
- Nudity is not really illegal because it is harmful, but because some people feel uncomfortable by others that act differently. What is harmful is giving in to the least tolerant people in society, and upholding the legal doctrine that offending others by being different is a crime.
Many people have similarly claimed that libertarians not wearing a mask hurt the libertarian movement. However, measuring and predicting the effect of activism is a difficult task. The best thing you can do is be a good neighbor - live honestly, peacefully, and with integrity. Activism which annoys some people in the short term might inspire other people in the long term. (Although, we don’t recommend annoying people without a good reason!)
Generally, we think it’s important to exercise your freedoms. If you nominally have a freedom, only because you haven’t exercised it and had it taken away, then you never really had that freedom in the first place!
And, if you don’t exercise your freedoms, perhaps by occasionally being nude or open carrying, than first such behaviors become weird, and then deviant, taboo, and prohibited.
You have the right to require clothing on places you own, privatize and own public areas, and dissociate with or try to ostracize nudists, or implement any other creative, non-aggressive solution.
The Porcupine Freedom Festival is an opportunity to showcase the libertarian principle in action and to recruit new participants to the Free State Project. The purpose of Body Freedom Village at PorcFest is threefold:
- It is fun. It is incredibly liberating when you the clothing that is usually forced upon us, whether we would wear them voluntarily or not. It brings people closer together and builds community. It shows all participants - Free Staters and prospective movers - that we are a diverse group, with lots of interests, and do lots of fun, creative things.
- It raises awareness about government clothing mandates, which are an absurd function of government, applied differently between sexes, and enforced with severe punishments.
- It reminds attendees that Free State Project is a libertarian project and PorcFest is a freedom festival. There are countless, larger conservative and statist festivals where organizers and attendees mandate conformity, suits, and ties! This is a festival for people who want to experience Liberty in Our Lifetime.
The answer is complicated and evolving.
According to the PorcFest Terms & Conditions:
I understand that some attendees of some Events may engage in expressive activity and dress, which may include partial or full nudity and other types of expressive activity. I agree that such expressive activity and dress is not indecent nor offensive to me, and that I have decided to attend the Events with full knowledge that such expressive activity and dress may occur. If I am accompanied by minors at the Events, I acknowledge that I have made a choice that the minors may be exposed to the expressive activities and dress that take place at the Event, and that I have exercised parental responsibility and control in bringing the minors to the Events. Should I find that any activity at the Events is offensive to me, or to any minors accompanying me, I acknowledge that I can avoid such activity by, among other things, leaving the vicinity of the activity or leaving the Events.
These have been the terms since 2015 when they were first created. Such radically libertarian terms attracted some eventual movers to check out the FSP!
According to long time attendees, nudity has been a part of PorcFest, like while playing frisbee or sunbathing, since the beginning, but we assume mostly in the remote areas of the campground. Since 2015, there’s been mostly enthusiastic support from the participants, a couple of vocal (at times, threatening) opponents, and concern from the organizers. The owners of the campground are now aware of Body Freedom Village and were happy help us find a good spot.
Last year, for this year, the organizer banned nudity from common areas (e.g., pools and field). This issue was passionately debated, as many people were concerned this was diluting our libertarian ideals to be more palatable to conservatives.
We do not think BFV violates any laws. After all, Roger’s Campground is private, nudist camps are legal in NH, and the potential for nudity is well advertised in the PorcFest terms and through our event advertisements. But there are oh-so-many laws and we can’t guarantee you won’t get in trouble for anything.
It’s important to be precise with our words and meanings!
Libertarians are against initiations of direct force. We are not against, e.g., employers “forcing” employees to work, or a new business “harming” the profits of an existing business.
You need consent when not getting it first would result in an initiation of direct force. Simply open carrying, or not conforming to a dress code, is not force, and does not require consent. A more appropriate word for this would be permission, and libertarians don’t believe you need permission to exist or do non-aggressive things.
We think it’s great that you want to give your kids more autonomy. But, please remember that they may encounter people with different viewpoints and lifestyles. You can’t demand that everyone they encounter to conform to your household’s religion, dress code, sexual orientation, etc. PorcFest is a microcosm of a free society. It’s peaceful and safe, but it’s also not just for kids.