Knowingly giving a deflated ball as your game ball is cheating.
The prescribed penalty is for the inflation of the football to be adjusted by the referee, with the pump that is required by rule to be provided, before the ball is put in play.
Taking advantage of a weak inspection system doesn’t make it any less cheating.
Tell that to Aaron Rogers, who described his efforts to do just that...with over inflation...in November. No screams...no investigaions. Really, it’s a lax inspection system because no one cared as long as it was vaguely close, until they got to play gotcha this time.