If I understand well, when being part of a pool, you are asking to solve problems that are easier than the real one, typically finding a hash starting with n zeros instead of n+1 or something. And you will be awarded some fraction of BTC depending on how much "easy" problems you solved.
But when (if) you find by chance a solution to the full difficult problem, why would you send it to the pool and not submitting a block to the network by yourself and not sharing anything?