As usual the guys from other states are hypothesizing on a CA situation without the slightest clue on the law or other things in CA.
Yes many Starbucks and similar establishments have outdoor areas, because we don't have snow or bad weather to worry about most of the year. And smoking indoors is illegal in businesses and cities or businesses can regulate smoking outside.
And calling for back-up is a nice concept, but it takes time and frankly you don't call for back-up to tell somebody to not smoke. And he sure as hell didn't have time to retreat and call for back-up once things went sideways.
And yes that would have been a good shoot for a (legally) armed civilian. CA has no duty to retreat in that circumstance.
Penal Code
197. Homicide is also justifiable when committed by any person in
any of the following cases:
1. When resisting any attempt to murder any person, or to commit a
felony, or to do some great bodily injury upon any person; or,
if the civilian was carrying illegally he would have CCW violations to worry about but not homicide.
(Yah ever notice how many ACLU Blame the Police First types we have on this board?)