Newspaper street scam

Hey so I've noticed in mostly every capital or big city of Europe (I'm from Bucharest but live in Milan) there's this trend of people that have a mobile cart and that stay around touristy areas to take instant pictures of people, printing it out and using a template, to make it look like an old newspaper with a goofy title. They apparently do not have a fixed price and just ask for donations (obviously for it not to be considered a comercial activity). My question is how do they not get picked up by the police because i don't think they have an authorization for being there (im pretty sure u need one even if you re not theoretically staying in one place) and how did they expand everywhere since apparently they don't belong to a higher common brand or network. I'm really curious about how they operate. E.g. there's an insta page called street.press