Perhaps I am wrong in this, but I know I have read enough in various posts, ads, etc to lead me to believe that by calling it a "donation" and by claiming "any acts performed are by consenting adults and any money exchanging hands is purely for time spent together" is a means of sidestepping the law and perhaps sidestepping the moral view that anything that takes place here is "prostitution." Hell, I freely admit that I am one of the biggest rationalizers that I know, and I used this very premise when I first started hobbying myself.
So I realize I might be making a leap, and I am sure I will be smacked down if this is an argumentum ad populum, but doesn't that whole premise get shattered by upselling?
Provider: It is $x for my time...
Monger: What about abc?
Provider: Oh you want that? It is $Y extra
Right there, you have just now put a price on a sexual act and made it impossible to call it anything but prostitution and a monger who takes you up on said offer as anything other than solicitation.
Note, I am not saying people shouldn't upcharge for services, but if you are going to do that, do you at least realize what you are doing? Any chance you had at making any claim that you aren't selling sex is thrown out the window. Plus you are forcing said monger to the same realization.
It is just something that I have always wondered about providers that choose to upsell as opposed to just having a higher rack rate as your donation and saying it is all inclusive whether a monger chooses to partake in all of the menu or not?