Erm... I think there's a difference here.

Sure on a personal level you are unlikely to be prosecuted if you are just discretely listening for your own personal use.

However, the minute you start passing on information about what you've heard or by setting up a live feed, then it's a different matter.

As for a UK reg airline rebroadcasting the content over the IFE.... ain't going to happen. Don't know what the US law is that allows whoever was mentioned earlier to do it.