My current workstation has no audio card, so I've been listening to music via a Bluetooth headset and a USB bluetooth dongle. Since the headset has a jack for optional cable audio in, I figured that it may be possible to output the audio through the input jack while the headset is receiving data via bluetooth. Sure enough, I can feed music into the headset via bluetooth and output via the 'input' jack:

Might I risk damaging the headset by repurposing its audio input jack as an audio output jack?