Portland is becoming a popular site for people who want to show that they can do things that are legal, just not things usually done.

Earlier this month, Congress Street was home to a parade of topless women, who were asserting their right to appear in public while shirtless, which is the same as it is for a man.

This Sunday, Back Cove will be the site of a demonstration by gun rights enthusiasts, who will be asserting their rights to openly carry firearms.

The two events have a few things in common. Just because it isn’t illegal to do something doesn’t mean that you should do it. There are social norms and customs that govern our actions and, like the law, they are worthy of respect.

The events also have this in common: They are provocative acts that could take their supporters to a place they don’t want to go.

There is no law against open-carry of firearms because we haven’t needed one. The vast majority of gun owners take their responsibilities seriously. People who keep guns for protection, for the most part, do so in a way that doesn’t interfere with other people’s security.

Gun ownership is a constitutional right, but like free speech and other rights, it is not without limits. The Supreme Court has ruled Washington, D.C.’s gun control policies went too far, but it did not strike down all legal restrictions on gun ownership.

Organizers of Sunday’s event say they are not planning to cause trouble. They say they want to demonstrate that open-carry is not only legal, but can be done responsibly.

But like the topless protesters, the open-carry advocates may not like all the attention that they attract.

A group of gun control advocates has already announced its intentions to protest at the same time on Sunday, and it will likely get a chance to give its side of the story. Images of a large number of armed strangers milling around Back Cove may make some people feel more safe, but it is sure to make others feel much less so.

The best argument for gun rights in Maine is the overwhelmingly responsible behavior of most Maine gun owners. Low crime rates appear to be compatible with Maine’s history of minimal restriction of gun ownership.

It’s hard to see how this event will advance that case. Violating Maine’s customs by encouraging people to provocatively display their firearms in public could lead to other changes as well.