Worst case, someone could create a device they drop in your bag that records everything from your headphones. Maybe even in the shape of a USB drive or something. I believe the "fast connect" protocol allows you to be "connected" to more than one device at a time, so you likely wouldn't even notice. Another attack would be to set "coffee coasters" around an office as a janitor, that snagged audio from any nearby pods.

Essentially, you basically have the hard part done for any bugs, you just need to build a device with a little battery, a BT transmitter, and storage; then you've got high quality audio near where anyone is speaking.