Via Large Hearted Boy, I found a couple of bootleg Charlotte Martin shows (who I know very little about, but she sure is perty). The source listing–meaning how the bootlegger captured the audio–for one of the shows reads like this:
Source: SP-BMC-12 (mounted in croakies) -> SP-SPSB-1 @ 160Hz Bass Roll-off – > Nomad3
Huh? Mounted in croakies? After a bit of googling, I learned that croakies are a type of sunglasses, and that bootleggers sometimes mount microphones in them. Who knew? I’ve enjoyed many a bootlegged concert over the years–how many of them came via surreptitious eyewear?
DarrenBarefoot.com 
actually, i think “croakies” are a sunglasses accessory, not the glasses themselves. from what i recall, it’s a polypropylene tube with an adjustment bead in the middle. on each open end of the tube, you slide in a sunglasses arm to hold it to your face when playing light sports. you can also use it to dangle the glasses around your neck when not using them.
Quite right, actually–that rings a bell.