I don't know much about Bitcoins, but is there a large risk of tainted workers in a pool that are reverse engineered and have knowledge of the part of the algorithm they're helping with? Then, if they detect they mined a coin, they disconnect from the pool, don't report the result, and take all the profit.
I couldn't find anything with a quick search, but would be interested to read more about (client-side)? security vulnerabilities of pooled mining.
I mentioned that in the article. A miner can't "steal" a block they solved for a pool. The miners are working on a block that pays the reward to the pool. If the miner successfully mines a block and bypasses the pool, the address in the block is still the pool's address, so that's still where the 25 bitcoins go. If the miner tries to change the address, the hash changes and the block is no longer valid, so the miner can't submit the tampered block.
There is a theoretical attack where the miner throws away a successful block, so nobody gets the reward and the pool suffers. But it's a whole lot of work just to annoy people and this solution-witholding attack isn't viewed as a real problem: http://bitcoin.stackexchange.com/questions/1338/how-is-block...
I couldn't find anything with a quick search, but would be interested to read more about (client-side)? security vulnerabilities of pooled mining.