people are watching and examining deepbit like hawks, I doubt deepbit will do anything fraudulent. Plus why would any established pool destroy their own investment by destabilizing bitcoin network? the reward is tiny vs the potential loss. What we need to watch for is if any non-established source has control of hash power over 50%.
But what if someone hacks deepbit and gains control of the pool?
It would be a short lived win, because deepbit doesn't control the pool's nodes. As soon as the breech was noticed, and it wouldn't take all that long, the nodes' owners would just starve deepbit of it's collective resources and the takeover attempt would be useless.
But couldn't someone with control of 51% script it so they 'found' 1,000,000 blocks in the span of several seconds?