If you plink 'em in the neck there is no autonomic reflex. It's a smaller target than the ass and you have to hit bone.
I'd sat the risk of a miss is way too high on that. And really, with a gun in his hand there is no real shot that can be counted on to prevent a reflex pull on a trigger.
In prison it is different, we are talking an edged weapon. Preventing him from doing a slice or a stab is a lot easier than preventing that 4 pound pull with one finger.
The older I become the more I am convinced that the voice of honor in a man's heart is the voice of GOD.