correcting dealer when not in hand, etiquette question

Last Month I played live poker for the first time at the MGM Grand, I couldn't believe the errors by dealers. I was playing 2/4 limit and twice I corrected incorrect calls by the dealers on showdowns on big pots(relative). I wasn't involved in either hand and the people involved didn't see the miss call either! The losers that were the original winners were not very happy both times. Should I just keep my mouth shut since I am not in the hand? Obviously I would correct it when I am in the hand. Just doesn't seem fair when the dealers misses a straight(and the person playing also).

Sorry for the long post, this is my first one!