Better way: a tiny projectile traveling at a thousand-plus feet per second. 

Murica.

[quote=@HereComesTheSnow]
I'm not saying it's completely ineffective, you just might want to pair it with something else like a palm to the nose in a live situation where adrenaline's running high. Take no chances.

I help teach at my martial arts place. Part of my job's teaching self-defense with real-world situations in mind.

It's also my excuse for being really really anal about stuff like this to the point of being an asshole.
[/quote]

Eh, the way I see it, you're trying to correct a misunderstanding. It's very difficult to change someone's mind about an ingrained "truth", so you often have to be assertive. God knows how many times I've come off as an asshole trying to explain what I feel to be a simple topic to someone who just doesn't get it.