I have to disagree with you, TW, on the crescent kick to a knife, though we practice a similar technique. We practice with a crescent kick to the face from that type of attack (punch, stab)...
If you look at how far your attacker has to be away to hit them in the wrist with the crescent kick they most likely wouldn't be able to hit you with the attack in the first place, they'd be too far away...however if they are close enough to hit you their face is a perfect target for the kick...
Not saying you're wrong, because I don't know exactly how you practice the technique...that's just how we do it...
If you look at how far your attacker has to be away to hit them in the wrist with the crescent kick they most likely wouldn't be able to hit you with the attack in the first place, they'd be too far away...however if they are close enough to hit you their face is a perfect target for the kick...
Not saying you're wrong, because I don't know exactly how you practice the technique...that's just how we do it...