allow auditory headsets to use different channels

[Roomba]

I think that's a niche enough problem it shouldn't be a major concern - only the ultra-powergamey people would do it, and it's not like having access to private channels besides sec is an especially notable advantage. It would be far more practical for everyone to e.g. grab a toolbelt and insulated gloves every round and yet you don't see everyone doing it.