Question is: Would the miner inform you if you found a block or wouldn't it tell you anything, anyway? That way you could at least get annoyed because you come to the conclusion that solo mining maybe actually would have been more profitable for you.
As I understand it:Every time you see an accepted share, your client (phoenix, poclbm, etc) thinks it has solved a block. The pool requests an artificially lower difficulty setting, this allows you to "solve" blocks more easily. Every time you solve one of these easier blocks, you are credited with a share, a proof of work. Since the method to solve both difficulties is identical, the same work would be done to solve both. So the only real difference is your client reporting back more often, the pool interprets these "solved" blocks as shares, and knows the actual difficulty, so when a true solution is found the pool can submit the solved block, dividing the proceeds to everyone based on the amount of shares they have into the round.
tl;dr Your client couldn't know when you solved the actual block, only the pool.
I think this is right. I know (or rather, I believe) that BTC Guild recently raised the difficulty from 1 to 2 to halve the strain on the servers.
