Maybe its because you went first class, but wife and I being coach and the flight was completely sold out. At Heathrow I was told to put my brand new Wal with the oversize luggage & golf bags stack.
I was given the argument our US travelling musicians rules didnt apply in UK to take the bass onbaord, and that If I didnt want to put my bass in luggage, then I can just cancel my flight and rebook because there were no extra seats to buy on that flight. It kind of drew a security guard over to listen-in this little bit of commotion going on.
So in the cargo hold it went.