Well, I had to spend some money and work with the design for two months before I came to the conclusion that:
FRAME LOCK FOLDERS AREN'T YOUR BEST CHOICE IF YOU HAVE TO DEPLOY THE BLADE UNDER "STRESSFUL" CONDITIONS!
I purchased two Chinese made D2 steel flipper tab folding knives, both with titanium handles / integral "frame locks". (Don't ask what brand / make / model, etc., it's the frame locks that I'm focusing on.)
I carried one or the other, or both, every day for two months.
Every time I accessed / withdrew the knife from my pocket in a simulated exigent fashion (that's an ed-u-ma-ca-ted way of saying as if my life depended on my deploying the blade quickly), my fingers pressed on the frame lock bar and I could not generate enough force on the flipper tab to open the knife.
Same result with my non-dominant hand. Every day for two months. (No I'm not ambidextrous, I just think that you should be able to operate all of your daily tools - pens, pencils, cell phone, keys, flashlight, etc., with either hand.)
Possible contributing factors:
1. I have large hands, so regardless of shape or contour of the grip, my fingers always fell onto the lock bar. (The President doesn't have this problem, according to the FLOTUS.)
2. Under stress and adrenaline dump, the second motor skill you lose is fine finger coordination, so you tend to grab objects with your fist, not with your fingertips.
3. Interlimb sympathetic response: Or, what one hand wants to do, the other hand mimics. To simulate some of the time, I punched a heavy bag as hard as I could with one hand while withdrawing the knife from my pocket with the other hand and attempted to deploy the blade. Zero percent success. Each time, my blade hand brought the knife out of my pocket in a fist, and I had to reposition my fingers before I could flip the blade open.
Any of you familiar with edged weapon martial arts are probably familiar with this as well.
My first choice for a defensive blade? A short bladed, full tang FIXED BLADE. (CRKT Stiff Kiss or Obake.) I can get the blade out and working in about half the time it takes an experienced Filipino butterfly knife practitioner to deploy that blade.
My first choice for a folding knife that deploys quickly? The original Cold Steel Ti-Lite. The spur on the back of the blade near the pivot point is perfect for hooking on the edge of the pocket as you withdraw the knife from the pocket. Push down and back, and the blade locks into place with a satisfying "snap". It's faster than most automatics, because you don't have to find that tiny button (again, gross motor skills versus fine finger coordination) and worry about pressing the button before you clear the pocket (at best, you just sliced your pocket open, at worst you just sliced your thigh / femoral artery / naughty bits open).
The bitch of it was that I spent more money on those two Chinese made D2 / titanium frame locks than my CRKT Stiff Kiss, CRKT Obake, and Cold Steel Ti-Light Zytel put together!
Not "sexy" or a "grail" knife made of unobtanium, but very real. That's what works for me.
Hope I saved someone some time / money / skin!