... there are a number of well documented cases of aircraft ditching and people inflating life-jackets inside the aircraft and people needlessly ending up drowned.
Would you care to provide a citation to one of these well documented cases?
...from a store few used and even fewer knew existed
You're suggesting that some used the store without knowing it existed. An impressive achievement.
Shooting some for anything is never justified
Wrong. If someone is posing a clear and present danger to me or my family, and if the setting is such that shooting him doesn't pose a danger to others in the vicinity, then shooting him would absolutely be justified.
Obviously that wasn't the case in this incident.