There was a post on Reddit, I think, that explained that there were ports in the luggage bins every so many seats that were for for medical comms to run on. Som

There was a post on Reddit, I think, that explained that there were ports in the luggage bins every so many seats that were for for medical comms to run on. Someone plugging something into this port could play whatever they wanted from a computer. It's probably the same person doing the same joke over and over. The only problem for them is that AA could cross reference the travelers on those flights to figure out who it was, if it was a passenger using these ports to prank.