That's the idea behind the law. They want the animal to be able to shed a non-passthru arrow to increase it's chances of surviving a non-fatal wound.

Actually, mechanicals, especially the ones with longish, aluminum ferrules, worry me in the context of that law. If you hit solid bone and bend the ferrule, those blades won't close. A bent ferrule turns a mechanical into a barbed head. Anyway, that's off topic.

Doesn't look like bending the ferrule would be as big an issue with these heads anyway. Being stainless steel and weighing 100-125 grains, they gotta be pretty dinky. There can't be that much ferrule on 'em.[:-]