I expect chains to snap because they are more prone to snapping than belts. I have witnessed it on race and road bikes, have experienced it on a low mileage, well maintained, correctly adjusted o-ring chain on a road bike with 72hp and have seen a road bike that was written off following a chain breakage despite the rider bringing it safely to a halt without dropping it; the crank cases were destroyed, the barrels damaged, the frame and seat sub-frame badly damaged, the swing arm wrecked and lots of minor damage.
While the belt drive system in the M3W has it's share of issues and failure modes, snapping and coming to visit you in the cockpit isn't one that I consider realistic. With a chain I would not be so sure.
