I don't see a lot of active encouragement of leaving stuff at megalithic sites in Britain. That being so it could be argued there isn't a major difference between the two urges - both involve knowingly depriving others.

Anyhow, both wrongs against the majority will go on forever until someone puts their foot down. Tescos hardly ever prosecute and the NT (that has a byelaw saying don't litter) keeps quiet. Only the Rollright Trust seems to be sticking up for the wishes of the majority. Good for them, I think they're an admirable lot.