I used to own a Valet company. When they hand you a ticket it has an adhesion clause written on the back. It's only as good as a judge says it is. You would have to prove negligence which is near impossible once you have left the lot. It's likely you don't even have the valet stub to prove you even parked there.
I used to recieve many calls like this. Most were bogus claims, from transmissions to people having their own car stolen from us so it hits our insurance to Picasso's stolen from the trunk. So legit claims may have not been paid, but with the on slaught of calls for claims it's hard to tell. The moral is...once you drive off of the lot...you are pretty much screwed.
P.S. I never valet my own car unless I have too and then I throw at least 5 more likely 10 up front when I arrive for a 'no door ding' spot.
