Yes, I gave my GPUs a 5 minute cool down period near the end of the round. I don't think that deserves the loss of nearly all rewards from almost 2.5 hours of mining.
Just trying to be objective and helpful here. But I guess you could...
I appreciate your helpfulness. My cooling system is about as windy as I can make it, but I like to overclock to within the limits of it's heat transfer capacity. I'm trying to avoid going the liquid cooling route. I often do seize the chance for a cool down at the end of a long round, but when they peak up to 98C and there's no telling how much longer the round is going to be, I feel I don't have a choice. Only takes a couple minutes to get them back down to 40. After a cool-down period of my own, I find myself not really liking the waters in the Guild's pool, and as mentioned, most other pools either have the same scoring system and/or higher fees. While invalid blocks and scored out rewards give me the blues, I'm still jumping right back into Slush's pool.
What GPUs are you using? I understand water isn't for everyone, but if you want to try a better cooling method (assuming reference model cards) you can pick up an Arctic Cooling VGA cooler for between 70 and 100 bucks depending on which cooler you need. The coolers are more or less like the vapor-x coolers on the sapphire cards, only many of them have 3 fans instead of 2