The Mauser "Wing" safety
Is a very well thought out design for a military rifle. It is positive, allows easy takedown of the bolt, blocks the sights in the center (on) position, and every one I have ever seen (and I have seen quite a few) the full on position (bolt locked) has been stiff to put on or take off, making it unlikely to be done accidentally. If left in the center (up) position, it can be accidentally bumped to "off" fairly easily.
I once hunted with a young man who had a Swede Mauser carbine, and he was not fully versed in the Mauser safety. As far as he knew, it was off, or on (up). After he complained to me that after moving through the brush with his rifle slung he kept finding the safety had been bumped to off, I showed him the third position, and how stiffly it locked in place. I also advised him to carry the chamber empty when not actually hunting. We both felt more comfortable about his carrying the rifle after that.