I may not be the only one, but when I play with my 360 controller, the game picks up every single input and uses it, no matter how miniscule. This includes setting down the controller and putting it on a neutral position, as it's rare to have a stick sit perfectly at 0 in both directions.
I would recommend implementing some sort of threshold control for the player, so they can decide how far they want the controller to go before it starts being picked up.
