It makes me really angry actually. It's gratuitous littering. What's the matter with people that they can't visit places without swapping crappy bits of plastic? Why can't they just appreciate being there? Take a few photos. Think a few thoughts. Chuck a frisbee about or something. I think it encourages people to dig holes and move stones and leave unbiodegradable crap about. I think it's BAD. And I don't understand it. At all.