They never do! Although a lot of the times I see them wipe it off BEFORE they use it, which says a LOT about a person.  Once a fat was waiting for my machine so when I was done I cleaned it up, she got off hers (obviously not cleaning it), looked me straight in the eye and then rolled her eyes and started to fan the dampness from the cleaner. Like how dare she have to wait until it dries for her to sit on it. It takes like 5 seconds it's not like I doused it. I mean I don't really care, I am a gajillion times better than she'll ever be and I know she's miserable and dead on the inside.