That's something I find so appalling. The fact that you have to register every means of providing information to the public sort of parallels it, like saying you have to sign everything on the Net. We always have to be able to track you down. In addition, this person should have the computer expertise to take prudent steps to safeguard your privacy from civilian or government hackers. PGP encryption software.
Binary files take too much transmission time.
I will take steps to squish users who do this. Using this remailer to send death threats is highly obnoxious. I will reveal your return address to the police if you do this. Report any such incidents to the remailer administrator. However, all the best made plans of mice and men have weaknesses.