A new player has joined one of my informal sessions, and he objects when his opponents warn each other about a shuttle going out, by shouting "out" or "no". So for example he plays a smash, the non-receiving opponent thinks the shuttle is going out, shouts "out" or "no", but the receiver hits it anyway. Our new friend was distracted by the shout, and left the shuttle, perhaps he thought it was his own partner who called "out". The shuttle lands in and our friend loses the point. Two questions: 1. are you allowed to shout "out" before the shuttle lands in your court, and 2. do high level players warn their partners in this way?