Jesse Victors:
I've been running some exit nodes for some time now, and they're doing well. They've burned through many terabytes of bandwidth, and thanks to Tor's recommended reduced exit policy, complaints have been minimal. Clearly the vast majority of the Tor traffic is not malicious, but I have received some reports from other companies and from my ISP of hacking attempts: SQL Injection, XSS, botnet C&C, basic things like that. My ISP now tells me that they could reduce the reports even further by routing the exits through a "next-generation firewall" which apparently can detect an obvious clearnet attack and drop that connection a few milliseconds after the attack occurs.
You don't want that.
For Tor to work properly, once a packet is delivered to your exit (and the destination is accepted) the packet must be delivered. Otherwise, you are breaking the network and the relay will be a BadExit.
But you really don't want that because if you start looking at the traffic and selecting the traffic, then you become liable for what you transport (at least in Europe).