Ask her before agreeing...even if you make an agreement on payment DO NOT leave the hotel without checking out (don't let her keep the room for the night)...she can do anything from run up the bill with internet/movie/room service charges to smoke in the room...either way it costs you $$$$

I have done it once with a provider I was comfortable with. The price of the room was deducted from her donation amount. I would only do it if it was someone that I felt I could trust. AndI would not let her keep the room for other clients unless it is in her name. Good luck

(often for an outcall provider) to see only him.  SHE arranges the room & he reimburses cash for the cost PLUS her donation.
If the room is for her general use, he might offer something extra if she does not have an incall or it might be money up front deducted from the fee.  I recommend meeting slightly before the time outside, fronting the room fee and she calls you with the room number.  I have done this myself...  worked out fine.  
It's best to pay as you go & it's generally not a good idea to be "loaning" or being "owed" money by a provider.  Appointments become hard to coordinate or impossible, performance suffers.    
skb

It worked out fine. I trust her and there were no surprises. In fact, it was one of our best sessions so far Thanks again for the input.