Couldnt they be fake hashers, freshcoin pool.mn had a guy with a lot of ghs and turned out to be a fake hasher

this is what happened to him :

Hey Guys,

just to let you know this "megahasher" on Suprnova with > 2.5 gh/s was a fake share hasher..

This was the reason I had to restart stratum for a second, you should have seen a short disconnect but now everything is fine again and we are fake share proof with this new algo.

I've banned the user, froze his funds and will payout his balance to all other hashers as a bonus, its not much though, just about 100 coins which will be spread onto the next rounds.

This will happen to every other fake share hasher, so don't try, I've got good watchdogs running which filter those shares, you WILL be detected !

Page to prove: https://bitcointalk.org/index.php?topic=670939.760