I was in the local library about a year ago, and a son of Obama was sitting at a public computer gleefully recording porn to his cell phone, in view of everyone.
The librarian was nearby in a heated discussion with several people, making it clear she did not feel she could intervene.
Was not in my library system.
My rule in my branches is that if you can see it on the beach, it’s probably ok, but, otherwise we tell (politely) the person to leave or we get the police involved.
99 times out of 100 they leave right away.
At another branch in our system, where there is usually some kind of police presents at all times, the just get banned, but, that’s if the officer catches them. The staff know what they have to do.