[Nursie]

There are various limits on this, likely country dependent. And being free from legal sanction doesn't mean being free from public condemnation and shaming.

So, legal limits - if your behaviour constitutes harassment especially if you're targeting certain individuals, then it's likely to be illegal. Or if your behaviour constitutes 'disturbing the peace' in some vague way the police might put a stop to it.

But beyond that you're talking about the law but not everything is about the limits of the law, and the law is only a loose guide on morality. You can behave in a legal manner and still be doing something most people would consider wrong.

If you take your camera and try to record someone's kids up close in the park, you should absolutely expect to be told to GTFO, possibly by a whole gang of people. "Oh but it's in public I'm not breaking any laws, you have no expectation of privacy here" doesn't mean squat. Nor is it OK to film a bunch of girls like a drunken old pervert and try to say "It's not illegal".