Your being too pessimistic.
The situation that you described, could happen but its very unlikely.
And no, no one will blame you, its just as you said, all the pools have flaws, but they just keep it a secret.
Or lets say, the same situation you described happened with somebody, but they got a stale block... yeah shit happens.
But atleast they had a chance, that hey were willing to take, to find that block.
And on the other hand, think about those small guys, that keeps finding those blocks from time to time, and for some one its a game changer.
Maybe let this pool run, if there gonna be another server issue you can take it down, if you want.
But for some reason, I believe that your pool will work great, for the coming years, without any problems.