There is a reasonable expectation of privacy. So if you went around with a big TV camera and just started sticking it in people's face, that would get the cops called on you real quick.
Some Karens call cops for all kinds of reasons and cops often believe their interventions are backed by law when they aren't. What counts to answer "is it allowed" is what a court would rule I think
Somewhere your right to film someone in public crosses over into harassment, which is illegal. That line will vary in 100 small ways if you ask 100 people to define it.
There is a reasonable expectation of privacy. So if you went around with a big TV camera and just started sticking it in people's face, that would get the cops called on you real quick.