What steps does a Tor user need to take to ensure that he or she doesn't become implicated in other Tor users' criminal activity?
For example, I recently came across a Tech Republic article by Patrick Lambert saying that acting as a relay is dangerous:
You may want to act as a relay yourself. This will allow other people to use your computer to relay traffic. In order to do that, simply go to the Control Panel option inside of Vidalia and set up relaying. The thing to remember here is that by doing that, you are helping out the TOR community. However, you have no way to know what kind of traffic will transit over your system. Some of it may be illegal, and it may expose you to law enforcement actions.
I find this peculiar; I only thought people running exit nodes were putting themselves in harm's way, not relay nodes.