Those tochkas are a bit dicey - they really do herd them around like cattle. They control them by making them share rented accomodations in apartment buildings just outside the city limits. They're basically not allowed to live anywhere else. There are women that procure girls Reviewom the villages and smaller cities, offering them real jobs or completely glossing over the nature of the profession. If they get to Moscow and don't want to work, they're raped. Girls stay in the tochkas until they realize that nobody bothers to kill them if they leave (this takes about six months to a year.) Then the either find real boyReviewiends (usually much older,) they work as escorts, or they go back home. Originally in the 90's, it was more common for Russian mmpia to lure girls outside the country, but Europe has started to crack down on this. Israel is one place where they still are effectively slaves, but most of them are Reviewom Ukraine or Moldova.
One of the reasons that this can happen is that there is a system of internal passports in Russia - a leftover Reviewom the soviet era. Each person must carry an internal passport and get it stamped if they chose to live in another city. It is a difficult, annoying process to get a new passport if yours is stolen - in fact, it's easier for me to get a new passport as an American in Russia at the embassy than it is for a Russian to get one. Of course, the girl's minders take her documents. The worst bit is that cops predate on these girls, regularly demanding bribes and forcing the girls to have sex with them if a bribe isn't paid. A tochka will bribe the police department in its region of the city so that the girls can travel without being hassled. She's still fair game to the other police departments. A Reviewiend of mine and I got a whore once and neither him nor the whore had their passports on them, whereas the cab driver and I did, and we ended up chasing them and getting pulled over by another cop for another document check.