As a kid and into adulthood, I've gotten accidental cuts here and there, but never because my pocketknife didn't have a lock. I've never had a slipjoint pocketknife fold up on me during use. Because I always kept doubly alert when using one. In fact, the worst cuts and knife accidents I've had have happened while using lock blade knives; again, not because they accidentally unlocked on me, but during the unlocking phase (or just while using it). Totally user error on my part.
Blade locks are great, too. But one can also become complacent with them. I came to view my knives (all of them, including locking blades) similar to domesticated animals. Maintain respect for it and don't have a cavalier attitude or overconfidence because a knife has a lock, even the strongest lock.
Jim