Yeah--this is kind of tough. Because I think the "prospective tip" was something that, ten years ago, was only for if you wanted a prime spot up front. Probably 20 years ago, I went to Del Mar for the races, and I had a flight out of SAN that afternoon, so I was going to want to get out of there in a hurry. So I gave the guy a $20 bill on the front end and asked him to keep the car close so that I could get out of there. He did, and I did.
But since then, I definitely think the prospective tip to the valet has become less of a "this is an unusual deal where I need you to take good care of my car" and more of a "it is expected that I do this on the front end so that you don't fuck up my car." And I don't like that.
This sounds pretty reasonable. But there are some problems with it. What about complimentary valets? Am I tipping 20% of $0? That doesn't seem to make much sense.
And I am starting to get a lot tougher on tipping valets as the tip rate for valets goes up. If I'm going to tip you $5 or $10, then you need to take the little tag off my keychain, take the slip from off my dash or underneath my windshield wiper, return my seat to its original position, and not take my headlights off the "AUTO" setting. If you can't do those basic things to restore my car to the condition in which I handed it over, you're not providing me a service. You're inconveniencing me. And why should I tip you for inconveniencing me?