Chloe my experience has been that I have to provide my full name, room number and a contact number (usually my cell). I have no problem providing that as it is about security for the ladies.
I have only had one bad experience because of it and it wasn't the agencies or my fault but rather the hotel. When I arrived they had me in a non-smoking room and when I discovered it I was moved to a smoking room. The problem came up when the agency called the hotel to confirm that I was registered there, they put the call through to the non-smoking room, as they hadn't changed the info on their computer.
I got a call on my cell from the agency telling me of the problem and that the lady was not going to come up as the driver and the lady now were unsure of what they may be walking into. It was my first time dealing with the agency and they believed me, but the lady was not feeling very secure.
I offered to go to the lobby and give the driver a fee for his trouble but they had already turned around and headed back by that time. I was able to make it up to the lady and the driver at a later date with a successful booking, but not in the same hotel. I did get a free nights accommodation out of the deal at least. I explained that they had screwed up and it had potentially lost me a very lucrative account for my business.
So if as others have said if they are unwilling to part with the information that you want, then no date will happen. In the long run it is safer for everyone that way. This whole industry is based on trust and discretion from both sides. So it is not very much to ask.