In Mexico its a felony for a foreigner to participate in a political protest. They are much tougher on immigrants than we are.
...and they dare to prosecute...we don't let alone inforce our laws of immigration. Thus we are a fully open country.
IMO as long as foreigners know, and they do, that even if caught they can extend their time here indefinately thru our courts, who are more than willing to let them remain by playing that game.