One day I was about to leave a comment on a blog when I got a message saying Google disabled my account due to the fact that they "perceived a violation." There was a little form I could submit an appeal/explanation to, and they said they would review my account within 30 days.
Being cut off from the WoW blogosphere wasn't the worst thing in the world. About three weeks later I did get access to my account. Turns out I was hacked and the hacker used my account to spam a bunch of people -- not surprising especially since I used a pretty crappy password. Luckily my actual Battle.net account was under my main e-mail address, so ultimately no damage was done.
Still, all I could think was, "man, if this happened to my main email address, I would be so incredibly hosed it wouldn't be funny."