Mistaken Identity

At work we have to valet our cars as parking is in short supply and they normally stack the cars. I got off work today and headed over to the Valet area and they were super busy. There were two of them and they were running around. The parking was the worst I had ever seen. I waited about five minutes and the guy finally came over to me and I gave him my ticket. The night guy never brings my car around he always just hands me my ticket and then I go search for my car (luckily they park it in the same general area). Well today it was in the same area but it was blocked in. I walked back over to the valet station and as I was standing there a group of older woman came out of the restaurant next door (who also uses the valet parking). This blonde white woman (looked very well off), approached me with a $20 and said in a very loud and slow tone. "Do you have change for a, $20 your friend is pulling my car around and I want to give you guys a great tip." I looked at her, smiled and said "I'm sorry but I don't work for the valet" in perfect English of course. You could tell she was embarrassed and I really didn't take offense to it until she said "Well it's an honest mistake... I mean you have keys in your hand and your..."she didn't finished the sentence and kind of laughed and walked over to her friends as their car was being pulled around. It was a very strange experience.