Ok.. I know this scam. When in 20s, in NY City (those days pre 9/11) this was well executed. Taking cue, customer arrives, parks, gets room # and goes to the room. However, no one opens and he returns to the car. This route is critical for the pimp to understand, i.e. which car belongs to the customer. At this point, multiple options are executed to make the customer go back to the room. During this short travel (by customer) the license plate and thru it other relevant details are quickly determined. As the customer reaches the door this time however usually he'll find it open and he enters. But he'll usually find the room to be empty and a text indicating provider is in the bathroom and to make himself comfortable. This is done to give time to find out details about the customer. From this point onward its usually a blackmail via text asking for money to be left in the room and to leave. The bathroom will be locked from inside but not with a provider but the pimp. Also, the room selected would ideally have a connecting door to the next room for "emergency" intervention if required. BTW: this is often used by Vice too.