I was flying DUB-JFK(-LAX) in Feb. Both D1 and Y were wide open -- I was looking forward to a row of two to myself (i.e. poor man's business class).
The inbound was late, so departure was moved back 4 times, an hour at a time (luckily the first two were before I left for the airport). Just before boarding was about to start I was called to the desk and given a seat in D1 as an apology for all the delays. (D1 did go out with empty seats)
First time that happened to me.