I would think the main thing stopping the abuse is that the pool director generates the block to work on, including the payout addresses. So if you hash the block and find you have a solution, then sure, you can submit it yourself, but it's going to have the same effect. Looking at the Pooled Mining wiki page
, it seems that different pools have different procedures for doing payout. Some have all the payout for generation go to the mining pool address, and some appear to add a transaction to the block that pays out to the pool members instantaneously on the generation of a block.
And yes, you could spend your time working on blocks with just your own address, but then you wouldn't have hashes to send back to the pool as proof of work, and you'd pretty much be solo mining.
I don't mine, I hope I got this right.