"He just told Provider A that he has only 'X' amount in available funds. What if he sees two (or more) ladies on the same day and later on they all find out about it? The hobbyist becomes a lying conman."
Of course situations can be dreamed up that are undesired, especially if you start the scenario by saying the poster of the ad lied, but that's true of how things are now. What if a provider posts photos that are not of her?
I don't hear anyone saying "forget it, let's just go home to our wives".
If a price is mentioned in a reverse ad, I was thinking more along the lines of "I am willing to pay XXX for XXX and would like to hear from any willing providers". It could be noted in the ad if it is a one time offer or a standing offer.
It's up to the provider to decide if she's happy with the arrangement described, and answer the ad. If she finds that the offer was accepted by other providers as well, where's the harm? If she finds that he tipped another provider but not her? That's life.
Nobody, male or female, has to participate if they don't want to. I'm not sure if I would or not, but that's no reason to say it can't work or it shouldn't be tried. Like I said before, the downside as I see it, would be less advertised specials being posted. Hmmm...
On second thought, it would never work.