Is it self defense if you put yourself in a position where you need to use self defense? No LEGAL reason in this world for that grocery clerk to follow this guy outside. Sure it was self defense, but what caused this shooting?
" Mr. grocery store clerk, isn't it true that if you didn't follow this patron out to his vehicle, there would have been no reason for this deadly force to happen?".
It's a yes or no question.
Yes, the caveat: as long as the store owned the property.
A clerk can ask for car keys all day long, the customer can refuse all day long.
If the clerk went over the line, and accosted (physical contact) the man first. It would be a different story. Video would be required to substantiate this theory.