Folding out of turn - bad etiquette or just bad manners

[Matt Porter]

if your phone rings, place your cards face down in front of you and step back from the table to take the call. if you're not back to play your turn then dealer should muck your cards in turn. don't step away and say 'i fold' as you may be back in time to play your hand, or at least to give the illusion that you may want to continue to play the hand.