Oh I know what you mean - not that I wore a skirt (!), but pretty much every desk and chair at school had chewing gum stuck on it somewhere.
I wonder why Europa-Park doesn't have these problems, at least not to the same extent. Higher class of visitors perhaps!? Or maybe even the chavviest chav couldn't bring himself to deface the beautiful Europa-Park. I think it may also have something to do with the park's perfectionist approach to appearance, in that any vandalism etc. discovered will be dealt with pretty swiftly, whereas at AT/Thorpe etc. less seems to be done about it.