Question Author
Boo. It is simply a case of manners. If I go to the site and see that someone has drawn a picture, I will not do anything to it if they are still drawing. If they have finished I may well clear it and start again, since, as you said, it is a public site. But if someone is drawing (theraputic) and someone else comes and wantonly scribbles all over it in really big pen, then that is just really really nasty! And pointless!! It could be a child doing the drawing. I know this seems petty in the grand scheme of things, but who in their right minds would sit and wait for someone to come along and draw something, only to then deliberately ruin it?
Seriously!