If I were on this plane, I would be ticked. I think about when dH and I were coming back from France after a VERY long trip via Helsinki. We also had a long layover in Chicago and a long line in US Customs. On our flight home to MSP, if that orchestra started to play, I probably would have got up and destringed their violins. We were SO tired, grumpy and just wanted to get home. It was bad enough a baby screeched almost the entire trip... the poor mother tried her best, but our patience was severely limited after a long transatlantic trip, jet lag etc.
While it was a nice thought, there was not thought to the people who were in the middle of a very long trip, who were tired and wanted to sleep. Music is such a personal choice and I believe they overstepped by inflicting it on everyone without opportunity to opt out. What were people who didn't like it to do? Get up and be the party killers?