Gentleman and Ladies (still not sure which camp VK belongs, not that I care, but jsut trying to be polite)
May I suggest an extremely simple solution that should solve this “data protection problem”.
1. If you are booking on line, send a letter/email to BAEC, authorizing which people, whether family or secretaries or lovers or anyone you wish, to have access to your booking to have your unconditional authoritiy for BA to release any information requested or changes to itinerary/booking. Make sure that this is clearly marked onto your BAEC account if necessary with a code word. To make it more robust confirm that this authority should only be cancelled when BA receive written confirmation to the contrary from you.
2. If you are not a BAEC member, or if you happen to be making a booking via phone, take a deep breath and provide the names at the time of booking of those people you authorize to have access to your details.
I know its a hassle and one more call to make, but my understanding is that no organization can refuse for an authorized third party to be given authority to act on behalf of the ticket holder.
My account allows my wife and my office as well as some hotels to have access to my bookings. Yes its a pain to make the call and write the letter, but its a work around and it has worked for me on the past.