Actually, the only way to figure out who you are would be to go thorugh your IP address (which SDS has), then contact the ISP to find out who had the IP address at the time the post was made. So your scenario can't happen, unless your actual PC was compromised, and the police wouldn't go through all that trouble unless there was something really bad (or at least, I would hope that's the case...)
I tried going to bugmenot.com to get a password, but none of them worked. Darn.
CW