it will still unlock.
What unlocks it is when you turn, the outside wheel wants to spin faster than the inside wheel. This pushes the entire locker assembly ahead of the carrier, releasing the pressure applied by the crosspin to the ramps. Once this pressure is released, the drive gear can move inward, releasing from the side gear teeth, unlocking, and letting the outside wheel go as quickly as it wants.
For this to happen though, you need to have good traction under all your wheels. If the traction isn't good enough for the ground to drive the outside tire hard enough to unlock the locker, it won't unlock. If traction in the rear is bad and one or more rear wheels are spinning, it won't unlock.