Agree with most of the sound because the phone while playing a professor lecturing a classroom etiquette should be intended. If you want to use should seek permission first.
Agree with the majority Because the phone while playing Lecturer bad manners. Be attentive in class To request permission to use out of the room first.
Agree with the majority vote. Because playing phone while teacher lectures as bad manners should pay attention in class. If you want to use should be allowed out of the room before.