Just a quick question, So are you saying that no-one has ever successfully used a non-waved folder for defense? (Therefore proving one is viable?)
No you are misunderstanding what I am saying. Obviously people have used even swiss army knives to defend themselves.
What I am saying is that if you are going to carry a folding knife for defensive purposes you should carry your waved knife. Ideally you should carry a fixed blade. It is a well known fact that a folding knife is a huge disadvantage in a defensive scenario compared to a fixed blade. That is why I say any folding knife is not ideal, it should have a wave bare minimum.
If you are carrying a knife without a wave atleast be honest with yourself and be aware that it is far from ideal.
And btw if you have early enough warning that a threat is approaching that you have time to thumb open your knife; (or flipper, or auto, or whatever) then really you would be much better served using that time to escape and evade the situation. No one should stick around for a knife fight even if they think they are the only one armed.
There are few exceptions like if you are imobile or have to stay to defend an imobile family member. Otherwise if I have enough lead time to know a knife fight is about to pop off, including one where I am the only one with a knife, I am not sticking around.
Most serious attacks happen without warning because these are the attacks where it is too late to avoid. In these scenarios drawing a waved knife is a gross motor skill. Every other folding knife opening method is a fine motor skill which makes it markedly harder to do when one guy is on your back and his friend has punched you three times in the head already.
So yes it is possible to use a non waved folding knife for self defense, but I encourage anyone who is being realistic about carrying a knife with self defense in mind to carry a fixed blade or at very least a waved knife.