This isn't that difficult.
If you run a ToR relay (or anything related to P2P encrypted traffic) then under the AUP you are 100% certainly in breach if that is used for any form of illegal or defamatory content. The fact that you don't know what the traffic is does not matter, you're facilitating the end users in whatever they're doing, and you knowingly facilitating any uses, good or bad. So if the traffic is helping some pro-democracy underground in China, that's legal in this country (albeit not under China's third world dictatorship) and would be fine, and you can claim the high moral ground. If it's P2P film or other copyrighted material sharing, some UK based fundamentalist group, illegal "adult" content, organised crime communications, foreign spies, or a Wikileaks hacker trying to access the Pentagon's systems then you're still helping those ends. It's unlikely you'd be prosecuted solely for running a ToR relay, but VM could certainly terminate your connection without notice, and still claim any early termination fee, and if the uses were serious enough you could put yourself on the radar of the men in dark glasses.
Ask yourself the question: There's a shed-load of traffic passes through ToR and similar services every hour. How much of that is "just cause" traffic related to journalists defending freedom or activists working to get freedom? And how much is simple illegal file sharing, extreme p*rnography, hate content, crime or espionage traffic? I'm guessing that less than 5% would be just causes, and all the rest is trying to hide from inspection for a very good reason.
You might disagree with my thinking, but if you run a P2P encrypted relay, you're knowingly taking the risk.
