As others have mentioned, I keep the boarding stubs until I see the flight credited. I've had problems with UA credit for US flights, even when my US# is on the boarding pass. It took over 3 months to remove the UA flights in order for US to credit it. I just checked my US account and it is still not there for a 2/24 flight. My other problem is DL-NW-CO. I have my NW# on CO and NW flights up until boarding, where my Silver status on NW may mean an upgrade. If I don't get upgraded, then I hastily switch at the gate prior to boarding to my DL#. This is a pain for the GAs and for me since my DL Gold status is meaningless for CO and NW upgrades.

If I have anything but my CO# on the legs of my CO metal that involve Continental Express flown by Colgan air, I get no credit, but CO is giving me CO credit after my requests for the longer connection legs, although those were already credited with DL mileage. I'm not complaining since the net result is more miles than I am supposed to get. I don't think it is accidental, since they have credited me this way three times with no credit for IAH to DRT on Colgan but RDU to IAH mileage on both DL and CO.

-outoftown