I have the MKs ezy on my brompton and I have never had a problem with them coming off.To put them on and off takes no time at all once you get the hang of it.You turn the ring to line up with the black dot and push it in and hold it while you push in the pedal,then give the pedal end a thump with your hand palm and the ring snaps to
the locking position and that's it.If you don't remember to thump the pedal then it will fall off.