If our safety and security when flying depends on not being able to identify what the specific aircraft we are flying on, then it's really time to stop travelling and stay on the ground. The bloody registration number is painted on the side FFS!

Not to mention that if you're flying inbound long-haul on BAxxx to LHR then a great clue is what 'plane departs LHR on BAxxx-1'. Set yourself up at LHR for a few days and you can probably work out what the planned outbound is for any given inbound.

Personally I'm quite happy to wait and see what turns up, but if someone wants to know the specific aircraft I see no reason why it should be a secret (albeit I can readily accept there's no real reason for BA to publish the info given it's really not relevant and always subject to change).