"I am not sure its a good idea that if you are belted in the bar parking lot you have a right to kill them."
If unprovoked, they have the right to receive whatever they get... IMHO
I just hope something horrible doesn't come out of this. I am sure some of us remember how stupid and invincible we felt we were 18 0r 19. I am just saying one day someone's son here could get in a stupid fight over a girl in a parking lot throw the first punch and get killed over it. I can think of lot of other situations where this might happen. The common law doctrine of self defense has developed over the centuries for a reason. That is past common experience.