Not so sure about scraping the bottom of the barrel - it all depends who turns up on the day. Surely, RAF VC10 or C130 pilots are quality applicants?
With regards to BACX pilots, the agreement is that anyone who applies gets an interview, even if their application is so bad that they would never have been invited to attend if they were from another airline. So the BACX pilots have a head start!
Sadly, the reality is that many of the BACX applicants show little or no enthusiasm for joining BA and few have done enough preparation. How can you work for BACX and not have a clue about the Oneworld Alliance or how Terminal 5 will be good for BA?! Willie Walsh - who???? Or you can't even explain why you want to work for BA?
There is no hidden agenda, the jobs need to be filled and are there for you to take. Do your preparation and then do some more. Show lots of motivation at the interview. And, finally, don't have the attitude that BA owes you a living.