I don't really see how EH or anyone else can keep an eye on everywhere at once. once someone's been made aware of what they've got what more can you do, you can't be checking on them every five minutes? Don't they have to presume that people whose land these things are on aren't completely ignorant and thick?
If you ask me they do however need to take this culprit's arse to court and make a show of him as much as possible. The site was protected by law after all.