I wouldn't make that claim unless a PPS member comes up with an example of how the privilege worked while they were travelling in Y.

Its probably all about flying in J. Last month after I got back to BKK from a holiday and unpacked my suitcase, I noticed that both the leather straps had been torn off or were tearing off on one side as if a baggage handler had been lifting the bag by the strap instead of the handle. I wasn't really expecting anything since I was already at home and it was two days after the flight, but I called SQ who first asked me which flight and seat number I had travelled on. They then sent someone by my apartment to pick up the bag, got it repaired like new and dropped it off a day later. ^

When I checked their Baggage Liability document the next time I flew, it clearly said that damage to the straps were not covered, so I can imagine that a Y passenger would probably be brushed off with that line.