Gothicman is right on target.  The other issue even with a legit agency is that the providers aren't always on the up-and-up.  I had one who, after I shelled out $$$ for an out-of-town outcall, try to tell me that that just got her in the door.  Since the agency assured me 'total satisfaction', I called them right away in front of the provider.  The PO talked to the provider who was pissed.  After she hung up she told me she would do what the agency promised but not happily.  I replied that she could have the option of giving me back my $$$ minus a contribution for gas & time.  I wasn't in the mood after that.

If the agency is in Vegas, you will. That fee will only get the girl into the room, usually nothing else. Sometimes you'll get a 30 second semi-nude dance, then the upselling begins.