This has happened to me twice. Once was on a regular DL flight from ATL to either BNA or MEM (can't remember) on a md-88. The plane had to go cuz it had a full load coming back.

The other was Cabo San Lucas (SJD) to ATL on DL 737-800. I was only one in FC with 3 F.A.'s. Why you ask this flight was so empty.......it was Sept 11, 2002. Guess people were a tad nervous to fly on the anniversary.