I dont think anyone has brought up another reason against... Dirt/crap/finger parts getting into the rotating assembly and increasing wear on the belts. Online guides are constantly telling anyone who will listen that you should keep the timing belt areas as clean as a surgery. Kind of makes sense really. With the crap on the roads etc I'd be keeping them covered.
dont put your hands in an engine bay while its running. unless your like sim and want 4 fingers. i run without them, looks better, thats the only reason. all about hard parking points.
