"Neighborhood watch". Every neighborhood has a house with a communist informant. They watch the neighborhood to make sure no one is doing anything anti-Castro or committing any crimes. If you're suspected, they throw you in jail and sort it out later. No one wants to get thrown in a Cuban prison, because few people return. It seems to be working, as crime, especially against tourists, is exceedingly low. However, this was just creepy and really made me appreciate the U.S.A., warts and all.