Have any of you ever made evil have physical consequences in your campaign (ie, roughly following the taint rules in Unearthed Arcana)? I mean, I know it'd be kind of hard to do based on actions, but there are a bunch of spells (ie, Animate Dead) that have "Evil" as a spell descriptor. I think it'd be fairly easy to say that every time someone casts a spell with that descriptor, they gain a point of taint. I wouldn't have any consistency issues, since the only evil spellcaster they have met was a lich who was wholly insane anyways. Recovery from taint would be as described in UA.
I couldn't follow the UA rules exactly, because by the time your taint level reaches your Con score, you die (and then rise as undead). If I'm basing it on spell-casting then people would die off pretty quickly before much havoc is wreaked. I'm thinking somewhere between Con*5 and Con*10. I'm also not sure what to do about the rule that every point (or 5, or 10) of taint takes away a point of Con and Wis. I mean, I want evil spell-casting to have real, physical consequences, but on the other hand I don't want my players to cry ZOMG UNFAIR! I'd be introducing the descriptors along the way (hacking cough, paranoia, icky yellow sweat, etc.) but I don't think mere descriptors will have the same impact (on the Munchkin, at least) that ability score penalties will.
What do you all think of the concept in general and the ability score penalties in specific?