things in people's engin bays, loose nuts & bolts, LUG nut (no idea), glasses, tools etc you name it. Once it's in the engine bay it's subject to getting to the belt. Your ALT belt can slip all it wants and it won't cause your engine to go in a split second - however if your timing belt skips a tooth or 6 front something getting into it or the cam gears - it's thanks for playing , here is the home edition board game. I think it's a real risk and I don't see a reason for it for *MOST* street cars.