It's not rude. It's standard operating procedure and they are used to it.
You're spending hundreds of dollars here. Try to get what you want.
+1
Unless I've booked someone in advance, I always ask to see the lineup. Never just settle for whoever they give you.
And if there isn't anyone in the lineup that you like, you can always leave.
Here's how I do it at the higher end places (e.g., Flirt, Muse, AGS, Pickering Angels)...
I walk in and ask to see who's available.
The receptionist calls the ladies to come out and say hi.
At the end of the lineup, if there is someone in the lineup that I like, I will tell the receptionist that I'd like to stay with XXX for YYY minutes.
If there is nobody in the lineup that catches your eye, I simply thank the receptionist and say that I'll come back another time. At these higher end spas, the receptionist will be OK about it, and may ask if there is someone or some type in particular that you're looking for, and she may try to make some suggestions of other ladies who may be on shift but weren't available to come out and say hi.
I'd suggest that you go in and meet the lineup a couple times and you'll see how it works. There's definitely no commitment for you to stay after you see the lineup.
Just a few other tips:
This works at the higher end spas that I mentioned.
There are a few places that don't even allow a lineup, or may give you attitude if you walk after seeing the lineup. I don't bother to go back to those.
At some places like Perla and Allure, the ladies are generally fully booked, so there may be nobody to meet in a lineup. (good for the ladies, but sucks for guys like me who like to see a lineup)
I can't speak for AMP's. That's not MCOT.
Good luck