There was some chat on IRC about a mining pool reaching 46%

http://blockchain.info/pools

What's the risk of a 51% attack.

I suggested that the pool itself is decentralized so you could not launch
one

On IRC people were saying that the pool owner gets to choose what goes in
the block

Surely with random non colliding nonces, it would be almost impossible to
coordinate a 51% even by the owner

Someone came back and said that creating random numbers on a GPU is hard.
But what about just creating ONE random number and incrementing from there
...

It would be great to know if this is a threat or a non issue