If a switch that you moved ends up failing prematurely they may argue that you've altered it, thus voiding your warranty for that particular part. Magnuson-Moss basically covers you when a dealer claims the warranty on your engine is voided because you installed custom seats. If the item you altered is in no way related to the part that fails, you can not be held accountable for the failure. Certain things do get a bit gray though, especially when it comes to suspension and powertrain mods.