the gun is just a multiplier. Let's say you have risk (r):
r = y + yb + r0, y>0,b>0 (b = 1,2,3,...,n)
where y = bad attitude, b = gun, r0 = background noise (chance of unintentional harm)
four generic cases (besides (y,b) = (0,0):
1) 0<y<<1, b>0
when y = 0, it doesn't matter what b is. there's no risk of getting shot.
2) y>1, b = 0
people you want to avoid; they're still dangerous even without a gun.
3) y>1, b > 0
same people as above, but now they have a device that allows them a longer range and more deadly consequences with much less physical effort.
4) y~1, b>0
what we have in the video.
There's several sides to the discipline, but no matter what side you take, whenever you respond to negative behavior, the rule is y << 1. Act, but don't react.
This is the fundamental important rule, but if you still want to optimize (i.e. generate the best emotionally stable background for your kid) then you can only reward good behavior and not punish bad behavior (which can often be turned into a reward by the child, making it a positive reinforcement to bad behavior). Sometimes you have to punish for their own immediate safety (or for yours or others) but it still doesn't have the long-term payoffs. Mostly though, you want to let nature punish them and continue to be the person they rely on for help when they fall on tough times, unless you think they should be on their own of course, that's your call; but they WILL make bad decisions. They will make sure you don't find out about them if you're a y~1. If that y~1 has a gun when he demonstrates his y~1'ness, he's going to raise the shock value. You may feel the urge to trivialize shock value, but think about how that might affect his daughter. It's not even worth the risk that you'll traumatize your daughter.
@ Hyrkyl: the point isn't to reduce b... that's where you're confused. The point is to reduce y. To educate parents about the right way to manage conflict. I don't care about gun laws, I care about social progress. That doesn't happen through making laws, but through spreading ideas.