What you want to do, when in Mame hit Tab to get the Mame menu. In General Controls Player 1, setup the spinner in places where it makes sense, like Paddles or steering wheels (by selecting the control you want to change, hitting Enter, and then spinning the spinner). That should make it work in any game that needs it. And no, accidentally hitting it won't mess up any game except maybe mouse-based games, and if it does mess something up, hit tab and go into that game's controls and make sure none of them are set to the spinner (you can clear settings by hitting Enter to select them and then Escape).