WHBM, I take it that you have never been to any southern European country where it is not only normal but many establishments would close if they did not offer valet parking, countries like ITALY, SPAIN and GREECE come to mind instantly.

Back to the subject, it is never expected that onetips on drop off. My tipping on pick-up is totally dependent on how far the lot is and what if anything is being charged for the service. If its stupidly expensve and the lot is within 100 feet and still slow, I may not tip at all.