Another reason for this is that when girls are with their boyfriends they get nervous and start to sweat on their upper thighs, therefore leaving a mark in the shape of an exclamation mark.
Girl one: Holy crap I was so nervous when Jim took me out to dinner, and because I was so nervous I left a massive exclamation mark on the chair! I sure hope he didn't notice.
Girl two: I know what you mean, I hate plastic chairs because I'm always leaving exclamation marks on them! Why can't these places just buy normal chairs with Cotton Covers, that would help out so much because there are so many girls who have to deal with this problem!
(On a sign at a fancy restaurant)
Lady members visiting the restaurant are reminded to place towels on the chairs before sitting down, in order to avoid leaving Exclamation Marks.
Have a nice day.
Signed: The Committee.