g1smd - 8:16 pm on Jun 13, 2012 (gmt 0)
There's loads of things that can be done.
You can return random or doctored content; maybe minor changes that can be tracked, or completely different content that they can republish all they want because it's garbage. You can also play around with the actual status codes that are returned. It's not just 403 that can stop bots.