Registering a game object twice does nothing. Unregistering it once unregisters it no matter how many times it has been registered. Unregistering a game object while it is in use is allowed, but the control over the parameters of this game object is lost. For example, if a sound associated with this game object is a 3D moving sound, it will stop moving once the game object is unregistered, and there will be no way to recover the control over this game object.