Why would Tycho limit his own income? He gets 3% of the pool, so bigger is better I would assume.
If the assumption spreads the block chain is compromised, his BTC income will be worthless in notime. And for this to happen, it must not be true. Some short selling jerk could easily throw in fake chains and claim double spending on some of the transactions deepbit validated. Until the mess is cleaned up, BitCoin might be dead anyways.
So unless a pools mission is to destroy trust in BTC, it's absolutely in their interest to never come close to 50% hashing power.