Last week in addition to the pool's bad luck i had (just) 5min connection drop, which resulted in 1/3 of the reward for an 11h block, very unpleasant, but not the pool's fault - you either accept, that because of the score system it is possible to have such cases or you choose another pool (especially if you often have connection issues).
I should add to this that despite what's been posted on here before, your expected value doesn't change with the way this pool is scored. It just raises the variability of it. We always tend to focus on the negative outcomes and so we all notice if we have a rig down for a half hour in a two hour block but get almost no reward. By the same token though, I've taken systems down for maintenance/changes and brought them up after a delay, and my reward for that block ended up being essential unchanged compared to if I'd mined constantly. Statistically it works out to the same in the end.