Better Damage Bonus for combat skills using Skill Adaptation perk

[Christopher R. Rice]

Originally Posted by GURPS Power-ups: Perks p.17

Alternatively, you can add
specific skill applications – like getting a parry based on the
skill – which techniques don’t cover. Either must be borrowed
from another, related skill.

So my question is this, could you buy this perk for something like Skill Adaptation (Brawling gets Karate Damage Bonus). Yes I know it seems munchkiny and I sure as heck would be leery about putting this in any game I run but could it be possible? Is it legal.

Thanks for any responses

Ghostdancer