Of course, the quickness and simplicity of the M1 / M2 Magna-Tech system wouldn’t amount to much if a lens was likely to fall out during a crash. That’s true, but I have found no reason to think that this is something to worry about. Unless you pry at a corner of the M2’s lens, it’s very difficult to dislodge the lens, even intentionally.
Each of the M2’s eight connection points (created by the eight magnets on the frame and eight on the lens) has a pull-force of 2.75 pounds. That means the total retention value between the M2’s lens and frame is 22 pounds. So unless you pull something in the neighborhood of 75 Gs, there’s no way the lens is going to work itself away from the frame.
Even if you were to experience a serious digger / face-plant on hard snow, I would honestly still be surprised if the M2’s lens came completely free from its frame, especially given the kind of precise prying technique it takes to remove the lens by hand. If it did, I don’t think the whereabouts of your lens would be the first of your worries.
In my mind, lens retention simply isn’t a point of concern with either the M2 or the M1."