Did you forget to switch handles when responding?

Or are you bipolar?

I've even stayed and hooked up with the friend while the one I was just with watched...or did Whatever...she didn't bother me.
I had visited the original provider,and said hey I believe I saw your buddy on the elevator...she then called her back up...

I think that much of the time it's a scam meant to separate you from your cash... but I did once actually encounter a travelling pair where the second lady didn't have anything else to do for a while, so I got a doubles session at no extra charge.  Bonus.  

I've heard about girls hanging out in the bathroom, but I've never had it happen to me.  I did once encounter a lady whose ad I had seen just leaving the room I was going to, but she was carrying a laptop and looked like she was going to go hang out somewhere while I visited.  Not especially subtle, unless she's careful, but she was dressed pretty casual, and could easily have been going down to partake of the continental breakfast.