If the guy wants to bolt after going to the trouble of having a shower in situ, then I don't think he can demand a refund, but it's probably good PR to give back 50% - ladies choice though in my opinion.
If the guy wants to leave after paying because the lady does not provide the services offered that's another matter.
Though we are not now that strength which in old days moved earth and heaven; that which we are, we are; one equal temper of heroic hearts, made weak by time and fate, but strong in will to strive, to seek, to find, and not to yield.