Random unlocking phenomenon.
If you lock your car and carry the key in your pocket it seems to be random chance whether your car stays locked after you leave it.
The two causes of this are:
The transponder transmitter is powerful and operates from a considerable distance.
The remote function keys are flush with the case and slight pressure is sufficient to trigger a signal.
I had resorted to protecting my key buttons with a slip on plastic case. It worked - no false signals and a secure vehicle.
The new key cover raises the case profile.
The supplier insists this is a decorative item only that adds no functional benefit. I believe it might make a sufficient difference to try leaving out the Smint box.
Clearly direct pressure over the key will trigger a signal but the gentle overall pressure from the pocket may cease.