The "spectators can't point out rules violations" rule is basically designed to aid cheaters.
I think you need to look up the definition of the word design because despite its widespread usage you evidentally don't know what it means. Otherwise you'd be suggesting that the people who wrote the rulebook deliberately put in a rule to help people cheat.
And that'd be in the running for most stupid thing I've ever read on this forum. That honour has some stiff competition, something any forum veteran can attest to.
The rule likely exists to prevent the strident interruptions that have affected past high profile events, such as one where a spectator started lambasting one of the players mid match for being lenient with tokens (I think it was the GenCon regional final where one of the players forgot the ACD token on a TIE phantom).
Edited by Blue Five