Nifft said:
More implications? How do you deal with intent in your game?
If I know a character is a particular alignment, and they start to do something that's obviously contrary to that I'll stop them and ask what's the rationale, motivation or thinking behind that action. I'll let them know what the consequenses of that action are.
Bob: OK, then. I come back later that night and torch the orphanage.
Me: Hmm. Bob's alignment is Neutral Good. Um, why are you burning an orphangage, now?
Bob: We know the gargoyle is hiding in there; it's the only way to flush him out.
Me: You know there are a dozen kids sleeping in in a locked dorm because of the killer stalking the grounds; they'll all die.
Bob: Yeah, well, sometimes you have to break some eggs to...
Me: You know that's going to mean your alignment shifts to Evil, right? Condemming some innocent kids to die because... what?
Bob: No way am I staying up all night waiting for this thing to come out. We know it's in there and this will mean it dies.
We'll fast forward past the part where Bob insists he burns the orphanage and I show Bob the door.
Me: You all wake up the next morning. You find Bob's horribly mutilated body outside; the garogoyle has claimed another victim!
A less extreme example:
Bob: Once his back is turned, I'm stealing that book. We need it badly, and he's holding us up. If we don't use that info by morning, all those kids die. Yes, I know I'm a paladin.
Me: OK, you steal the book, y'all go read the ritual, the gate closes. Bob, you're sure no evil taint remains in the area.
Bob: I may not be a paladin anymore since I stole that book, but it was worth it.
Me: Excuse me? I'm not frickin' insane. You may feel you have to make restitution to the man for the book you destroyed, but your status is fine. You have no dreams, you see no omens; the god seems fine with how things have gone.
Bob: You know what, I'm tired of listening to this guy. I steal his horse and leave. I need to get to town, quickly, to save the orphanage.
Me: Mmm. You're neutral good, yet you're going to leave him to walk back to town; you remember that werewolves stalk the woods after dark? He'll might get halfway to town before night falls. You don't want to throw him across the back of the horse?
Bob: His tough luck. He's got a better chance than all those kids.
Me: OK. (Bob has made a significant slide from Neutral Good towards Neutral; he's not outright comdemming the man to death, but certainly putting him in significant jeapordy, but he's also doing it for a good cause. Bob's still neutral good but if there was a scale where previously Bob was Good 7, he's now Good 4 or so. I keep this in mind and make note of what Bob does later).