So the solution is simple isn't it? Google Analytics filter > filter referers like Selenium (or the entire EC2 block).
Think about the goal of a scraper, it needs to actually walk through all the content. That doesn't look like a normal user at all. An individual request might look ok, but in aggregate the pattern of a robot pops out.
https://www.usenix.org/conference/usenixsecurity12/pubcrawl-...