I don't expect BA to email reminding me that my passport is about to expire.

I do, however, expect the computer to refuse to enter 14/7/2010 as a valid passport expiry date for a trip in 12/2010 (which I believe that it did automatically, taking the details from the BAEC profile without asking me to confirm them). Computers should be good at doing this kind of task.

If the information had been left blank, given the expiration, rather than cryptically stating "details already entered" without actually showing what those details actually are, it would have been obvious much earlier.