These are all good points, John. What I'm really arguing for is that whatever equipment is present at the venue, there should be sufficient information in the room, available to the chairs and their deputies, to manage it. We wind up engaging in ad-hoc debugging when the mics go down anyway, so might as well empower us to actually fix them. I think a lot of them just use 9-volt batteries or stacks of AA batteries anyway, so that's very easy to facilitate and relatively cheap as well. Just a matter of doing that inventory before the meeting starts, in the secretariat's copious and not-at-all-constrained free time during that period. Or getting a volunteer to do it. :)