Why would you be deploying the knife on the ground for a SD situation. If you have a knife and want to use it for SD shouldn't it be done when your on both feet.
Plus a knife for grappling if you really need one should be a fixed blade imo.
I always thought having a knife for SD meant that you keep the fight on the feet. I'm just a newb within Martial arts, but was just curious to ask.
P.S where is kaligman when you need him
I train to react to a situation before deploying a knife because in some situations by the time you reach and deploy the knife it is to late. Since my first reaction would almost always land up in a take down. I will already be on the ground by the time I reach for my knife.
The knife is a great tool to cut your way out of various dangerous holds you might not be able to get out of during grappling on the ground, such as a triangle choke hold.
I find the wave is also difficult to deploy when sitting in a car or being pushed up against the wall. So I rather train being accustomed to using the spydie hole.
Fixed Blades are not an option for me, I travel alot for work and the places I frequent, they are not legal to carry.