What kind of prank warrants a shooting?
Well the "fake robbery" one I linked to upthread is an example of that. Kidnapping pranks or "social experiments" around child abduction could also result in a violent response from people around them. (I will note that the link didn't result in that, but reactions to it suggests that some people would.)
As has been pointed out earlier, in the moment there isn't a difference between a prank and the real thing.