I agree with one one of the poster's comment that the issue here really isn't the deposit, but the fact that this escort is no stranger to the client (repeat hires before) and took advantage of the situation/relationship, and acted unprofessionally, which in the end hurts the escort in that what would have been somewhat regular income with a stable/reliable client is now gone.
Writing now as i just went thru the same experience (not with deposit). Multiple hr/afternoon/Overnight hires all went great, then went for a weekend and let's just say the escorts hands and mind were on his phone more than they were on me...and a supposed romantic intimate getaway turned into more a "coworker" in the same room situation. Needless to say i will not be hiring him anymore (at least not for anything longer than an hour) unless he comes clean with what happened