In the past, I've used Wyeast smack packs, where the instructions tell you to make sure that the pack is viable before opening so that you can get refunded for a dud.
I'm a baker, and I use dry yeast all the time in my dough. When I bake, I always proof (that is, let the dry yeast incubate in tepid water for a few minutes, to ensure viability). Many people say this is no longer necessary, so maybe it's a bit of a rain dance, but I figure that it's better safe than sorry.
Yesterday, I brewed with a pack of dry Muntons Ale yeast, and right after adding the initial LME to my boil, I took the yeast out to proof in a glass of tepid water (where it sat until the cooled wort went into my primary). My question is: for those that use dry yeast, do you ever proof before pitching? Is this a good idea or a bad idea?