I want some opinions to back my position (I'll tell you later) in an argument with my 18-year old stepson.

Our disagreement is this:

My lab's biggest weakness has always been that he breaks when he sees a bird fall, even if he is in "stay" mode. I need to break him of this. (It doesn't really affect his ability to retrieve, but means I can't duck hunt out of a boat with him).

The two scenarios are this:

One of us thinks the quickest way to breaak this habit is to use a German-style pinch collar, pulling back slightly when he starts to break.
The other says hitting the dog in the face with a cap everytime he starts to break is the more humane method- pinch collars are cruel.

What are the opinions here?