Hey Kano, you need to add another rule to the contest.
Why? I suspect there's some users with a lot of hash power and they are making other accounts to split their hashpower.
Look at the workers. Users with almost the same name 
And i think 250TH is too high.
If you are somebody with 249TH you have enough money to buy an Avalon in 2-3 days.

IMHO

I didn't say anywhere that he can't do that if he wanted to.
He's had 2 accounts for ages since he joined anyway.
That's not something new.

The point of the upper limit is so that someone with 500THs, who doesn't really care about winning one miner, wont win one.

If they do care, they can of course make a worker with 50TH if they want.

The lower limit is coz I don't want to attract hundreds of tiny miners to the pool.
The pool hashrate vs workers is very good. Lots of tiny miners makes that not as good.