Recently, I delivered a talk in a safety training programme. After the lecture, I went out of the training hall, and tried to talk to my office for vehicle pickup to my workplace. One of the participants came to me and advised me to remove portable microphone, which was given to me before the talk. My phone conversation was audible in the training hall.
This is a lesson for me. I should have switched off the mic and handed over to the program coordinator. I forgot this. The other side is whatever I utter also will be audible and any loose talk (which may happen) would have put me in shame, if not in trouble.