This wrenches at the gut, but unfortunately we're in the position of pitting our interest in the past against an unstoppable force of nature: stupid, careless people seeking easy pickings or cheap thrills. What are you going to do? Post guards to keep the ruins from being ruined? These people are like bacteria breaking down a fallen tree. Unlike bacteria, of course, they know what they're doing. They don't have the right, but they can't be effectively stopped. Across all of human history and throughout the world ruins that haven't been guarded have been plundered. That's my sad take on it.