This is an absolutely fascinating thread, and I really appreciate reading and learning from all of the different view points.
As every situation is different, I don't think you can apply a "one size fits most" approach to hotels and play dates, but here are some considerations my wife and I have discussed over the years.
We look at play dates (first dates especially) like we are inviting someone into our world and on a "date". So my wife and I always pick up the cost of the hotel rooms because we see it as we are inviting someone over. We also prefer the atmosphere and safety that a hotel can offer, and so first dates are always at a hotel even though we could technically host at home.
With regards to drinks at bar before going to the room, my wife and I really enjoy the humiliation of her making me buy his drinks. She has shared that the act of making me pay for their drinks while she takes him to the room is something that makes her incredibly wet. So that is something we do more for our personal enjoyment. We have had a few Bulls offer to pay for the drinks, which has been nice, but unnecessary, as she quickly interjects with "Cucky will pay, let's go to the room".
The one scenario where we are okay letting the Bull pick up the tab on the hotel is if the Bull invites her over. We much prefer to play together, but on two occasions in the last three years (one while travelling and one local) she went to meet the Bull at their hotel room alone. In both cases our thinking was that the Bull already had the room anyway and so we didn't offer to compensate them for the room, nor did he ask, but after reading the comments in this thread, perhaps it would have been better to offer something.