My question is what else is in that pocket with the knife? If its just the knife sweet, but if you are going to be fumbling through a packed pocket i.e.: flip line, allan key, chapstick, lighters and snacks then I would still highly recommend one on the outside as well for those heat of the moment situations.
Side story, I was always taught to wear a knife on the outside of my vest, yeah there always in the way, but if you find the right fit its manageable, and yes I have lost many ( the hair tie trick works pretty well). Any ways I began to slack, became more of a private boater than a commercial, and started to carry a folding knife in my vest rather than a fixed blade on the outside. I had really only needed my knife to make the occasional sandwich or cut a random rope at camp so it seemed logical. I have know many other boaters that haven fallen to these trends.
This year during a high water run on the Ark my wife and I flipped our raft, during self rescue we got pushed into a strainer with me on the upside down boat and her tangled in the oar leash. Things started happening really fast, I reached in my vest for the folding knife, pulling out chapstick, tools, carabiners and other trash, dropping my knife, unknowingly on the drain holes of my upside down boat, I paniced, jumped in, ninja move untangle her and we both swim under this massive log . Once out of the water I could see my knife sitting on the boat.
I got home and ordered two new bear claws for both of us and We still carry very sharp folding blades in our vest
Just some food for thought in making a decision, things could have gone very differently for both if us something unseen was under water during rescue, someone was watching out for us for sure
maybe one day Ill share the go pro with y'all