I can see the logic in putting the transmit signal above the av head, but in a crowded place, where an av often moves away leaving their name label adrift or high above them, wouldn't it be more useful to see the NAME of the person speaking, not the av?
So I'm thinking the signal should appear inside the name label HUD (each side of the name might be the best place). Then it would be easier to instantly see who is speaking, and not have to try some weird camera position to work it out, by which time they have stopped speaking...