When Ernest designed the Commander model, I think it was in the early to mid 90's, initially it had a deployment hole and no wave. As the story goes, the military units didn't like the hole and requested a hook to catch enemy's blades during combat. Ernest designed the thumb disk and blade catch feature and gave it to the SEALS. They then found by accident the blade catch doubled as a pocket opening feature. Thus the wave was born. This is a paraphrased version of the story, there is the full story in a thread here but I couldn't find it.