Sousveillance

There could be other issues to mention such as someone being topless behind a fence is expecting a certain amount of privacy, even if it's easy for you to see because you are on the second floor nearby, and things like that.

There are other sensitive areas that are posted prohibited as well.

Some of these things have not been to court in various areas or circumstances to really see how "right to photograph" applies in various places / different people.

Certainly one might expect that people on public payroll in a public place should expect certain transparency in actions, however upskirt filming marilyn manson in line at a burger king may lend to some issues (civil and criminal in some juristictions).

I think some also have 'rights to their likeness" in various ways and copyright issues as well. Paparazzi may have lawyers who are willing to make it expensive to debate some issues, however filming a phish concert or other performance from a hill and sharing the video on social media is likely to raise a different team of lawyers who would be happy to have such a debate in courts.

So, there may be certain established freedoms to record many things in the US in many places, with some case law to back it up, I don't think it's good advice to say "you can record anything you want in public" and have people not be aware of a multitude of issues that could arise.

I believe private property owners can even sue if you use their barn in a photo in some cases.

However I must admit it's been more than a decade since I really looked into these things, and have only skimmed some articles relating to this issue in the past few years, mostly to do with filming public employees, so definitely not legal advice or anything, etc.