Fact of the matter is this, they act like an open rear until one wheel spins up and then the governor applies pressure to engage the teeth on the side clutch plates. The big problem is when someone stomps the pedal and one tire immediately spins up to 40 or 50 mph and then the governor kicks in the clutches. If you are on soft dire, gravel of mud you may get away with it but most of the time it is someone pulling off of the shoulder of the road onto the road surface. Now the right tire is going 50 mph and the left is going 5 mph and it is now on asphalt. Clutches kick in and BANG! It sends shrapnel right through the rear cover. It is no more of a locker than Chryslers Power-Loc. The Lock part is just in the name, there is no mechanical locking there.
