A final point is that forwarding mail for another person can hardly be made illegal in general. If I receive a message from person A asking me to forward it on to person B, and I do so, this is clearly a legitimate email message that I choose to send. To try to disallow this would be to put intolerable restrictions on email content. So, if this is allowed, it seems to me that I should be able to write a program to do what I am allowed to do manually.
I don't believe the analogy holds up. In dealing with it manually, police would expect that there's a chance that they could haul you into court and ask you for names and dates. In the manual situation, you are responsible as editor, a responsibility you're looking to get away from. The law would prefer that someone is responsible, so they may try to find a way to hold someone responsible. Chris