That's a good question, sirgrumps. The answer is simply that no one knows what the white knuckle grip is. That's why I hate it when people say, "Knife X sucks because it failed the White Knuckle Grip Test."
When someone says that a particular knife failed a spine whack test, I'll take the results at face value because I pretty much know what they're doing. When they say a knife failed a "white knuckle" test, I have no idea what they're doing; there are too many questions... What grip were you using? How mush pressure was being applied? Where, exactly, were your fingers? How big are your fingers? Can this test be repeated? Can other people make the lock fail? Etc.
The White Knuckle Grip Test is, for a slew of reasons, too subjective and unscientific to serve as a basis for defining the quality of a folding knife. If you feel that you may accidently unlock a particular knife then, by all means, don't use that knife. Unfortunately, many people act like this "test" has some objective value, when it does not.