There's a possibility that someone was dumb and is actually using a seed with a simple repeating spurred or phrase, like "bacon" repeated 12 times results in a valid seed with checksum. I've actually thought of looking for one...
Discussion
Probably there are script that run every minute checking this sort of obvious seeds, ready to wipe them
bacon bacon bacon bacon bacon bacon bacon bacon bacon bacon bacon bacon
nasty banana nasty banana nasty banana nasty banana nasty banana nasty banana
one two three fork one two three fork one two three fork
etc.
I am sure the checksums aren't all correct on those, but you get the idea.