Post 4625 shows mic clipped to jacket? Then why have a microphone at the lecture?
The higher quality sound comes from the fixed microphones. I figure the lavaliers were provided as a contingency in case a candidate left the lecturn for some reason, sound would not be lost. The sound mixer guy can mute the lavalier so the sound to the audience isn't from two sources, and "turn up" the lavalier as needed.