I act all surprised at the disappointment before me and ask for the girl on the profile, when she can't be presented, usually with' Oh she is will another client' or 'she is not working today', I say I'll come back when she is working.
Most of the time they want to keep fairly quiet because of the neighbours, especially in hotels. Worst I've had is a few mumbled words, mainly in a foreign language but I can guess what they meant.
The wallet in the car trick, they know exactly what that means, I have genuinely done that and on returning with more than £2.50 in small change, she'd got dressed and said I thought you weren't coming back, I hear that a lot.
Note - 90% of the time they hide behind the door when they open it, I always keep a hand on the door and have a quick look at what is hiding. In the event of a walk out it is easier to be the first at the door for an easier exit.