A strange thing happened to us recently, and as I'm not a heavy DL flier I was curious as to what happened and whether this is something to expect in the future from DL.

We booked paid F LGA-ORD about 3 months in advance; no status. Selected seats 1CD. All was well up to and including check-in at T-24. At T-4, I double-checked our BPs to find that (a) we had been downgraded to Comfort + and (b) the F Seat map was full. I called to find out what was going on. First they said there was an aircraft change; there wasn't. Then they said there was a schedule change; there wasn't. There were weather delays between LGA and ORD, but my flight was unaffected. After a long call -- we were in the cab on the way to the airport by the time it was done -- they got us in F on an earlier flight that had been delayed.

Anyway, what gives? I've been FAMed before, but not after check-in. Certainly as paid F we shouldn't have been downgraded; looking at the list it seemed clear at least six pax had upgraded. Had I not called, we'd have been SOL. I'm nervous because I've got 3 other itins booked in paid F on RJs for much longer flights. Is this something I can expect in the future with DL? I've had my seat changed but never bumped out of paid F on UA or AA...