I assumed that it wasn't possible unless you were a spambot.

But, maybe somehow your dynamic IP changed and your browser cached the page so when you posted a comment, it was submitting an outdated form (with the wrong IP hash in it.) That shouldn't be possible becuase the pages on this site should never be cached (they are set to expire immediately.)

Does any of this sound possible? Or maybe a web proxy that cached a page when it shouldn't have? Or something?

If this happens much, I guess I'd need to remove the IP address requirement.