Actually in places like 37D, KPressure and similar places, you are actually paying "after" not "before". The setup of those places is that you enter a place tht looks like a ktv where you meet girls who theoretically sing, drink, and play games with you. Apparently you like the girl during your ktv session and want to leave the establishment with her. What she wants to do with you outside the ktv is your matter, not the ktvs (37D, KPressure, etc). What you are paying for is your bill for using their ktv facilities. There was no sex in the premises.
As you leave the ktv area, you learn, "what a coincidence", the managers of the ktv know a friend who has a cheap hotel room for rent that is in the same building. You don't have to go out on the streets to find a hourly hotel room and go through the usual hassles of finding a cheap enough place, giving id at registration, walking outside with girl where friends/family may see you, etc.
So you take up the ktv manager's offer and stay at their friend's hotel. Because the hotel is not taking a deposit (cash or credit) they require a prepayment of room. It is only fair as they are afraid you may trash their room.
Has anyone really tried to sing a song or two at 37D or KP?