The issue with that would they're in a stadium full of noise relying on Comms. Where Offside will sound an awful lot like Onside as will Goal and No Goal
I understand what you're saying but who ever got back from a game and said "great game, the referee was tremendously accurate he spotted all the slight obstructions, a handball than no one appealed for and that deflected off the players foot and disallowed two goals for millimetre offsides "