Well, they do ask for it, but I let them live with most of my characters. Just because my Kitty is far more fab'lous than they are doesn't give them the right to be rude. They always get punished.
The "alright, you had enough" is hilarious when they're on their knees with a tiny sliver of HP left. Though one time in Winterhold when I let the Orc lady live, she kept fighting the people in the Inn and got herself killed. Then a Redguard guy suffered the same fate by running into a few mudcrabs in the wilds of the Reach that promptly tore him apart.
I guess death was preferable to being beaten by a Khajiit dandy. 