At First i thought this case was completely unfounded too. After all anyone is free to tune into the radio and listen to the music that is playing.
The Reason this is such an issue is because it is called entertainment. Any place of bussiness i meant to pay royalties on music broadcast and played in their stores. They are being sued because the people working on the cars had the radio up to load so that everyone in the store can hear.
What does terrestrial radio (versus satellite or internet delivered content) have to do with the matter? The copyright holders who license their material to the broadcasters (any type) expect the same personal use/commercial use protections and royalties.
That officially even extends to organising a movie session for your colleagues in the office, certainly if you ask entrance fees.
I think that is more when you are asking entrance fees. The reason for this is that it is seen as making a profit off someone elses work. I think if it is just a gathering of friends and workmates and nobody is paying then it is ok.