Call me cynical, but I rather got the impression that this was the PR line to be taken. The real reason behind the change is to cut costs, by reducing customer interaction with BA Staff (costly) and forcing computer use, thereby freeing BA to tell pax who ring up about seating:

"If you are eligible for a seat, it will show in MMB. What you see in MMB is what you can have. If you're still not happy, check-in online opens 24hrs before the flight. F**k off and don't phone again."

Indeed, the phone prompts could even have an option "Press 3 if you would like to request a seat". The suckers who press 3 could then be given a pre-recorded announcement in the above terms. Brilliant. No human interaction at all.

But, as I've said, I'm a hopeless cynic and I'm sure the motive behind the change was altruism and warm-heartedness on BA's part, and not another half-arsed badly executed measure to save a few quid.