At some point the headset jacks on some airlines went from the proprietary two-prong version to a standard eighth-inch “mini” jack, which made way for this idiot.
The guy sitting in front of me — with blatant disregard for the keep-your-seat-belt-securely-fastened sign — stood up and surreptitiously ran a headset wire down the backside of his shirt. Presumably he was attempting to avoid the $5 headset-purchase fee and still listen to the movie, without the flight attendant seeing that his headset had not been purchased. So much for subtlety, since he’s standing up in the aisle — rather visibly to 75% of the plane — during this whole process.
I’m assuming that the “mini” headset jacks are normal on an Airbus A320, or follow a somewhat normal pin-out. The old two-prong style is still present as well.