Dupe voters, this is not a dupe. I wish answers only about teachers, not general members of the public. Please re-open
According to the BBC,
US President Donald Trump has said arming teachers could prevent school shootings like that which left 17 people dead last week in Florida.
A staff member with a gun could end an attack "very quickly", he said.
I doubt that any other country has tried arming teachers, so it would be difficult to say definitively; but is there any analogous evidence to suggest that he might be correct? (The good guy with a gun theory)
[Update] Perhaps we could reopen, given that we now know what happens when there is an armed police presence at a school where a mass shooting takes place? (Although, admittedly, we cannot know if a teacher would have acted otherwise)