All the pools should limit single worker lower then 30K hash/s,my dual E5 2697 only get 15k, 30K limited maybe enough for single worker,but the GPU maybe 10X or 100X more then CPU.
that is useless, if you set 30k limitation, he can still register lots of account in the pool and like the top 1 guy, he can still occupy 2/3 of network hashrate