I checked in at ONT this morning for DL696 to ATL. My seat assignment was 19B (757), and I was surprised to see Zone 1 on my BP. I had spoken to DL reservations earlier in the morning and had been told it looked good for an upgrade, so I thought that had something to do with it. I did clear at the gate, snagging the last F seat.

Previously, with a coach seat assignment, I think I've always boarded in Zone 2. I know the recent discussions on here have said pretty definitively that Zone 1 is for F only, so why did I have Zone 1 on my BP without a cleared upgrade?