Mistakes do happen, they'll always happen and you can only attempt to mitigate against it. However, this does from the outside appear to be a lesson on how not to do it.
A change to the seat booking rules was implemented with no announcement to either staff or customers. This change went wrong and was still not acknowledged for longer than should be acceptable. When incident/problem management* kicked in it still appears that the staff were not communicated to as shown by the varied and confused replies from the contact centres. We then had a fix applied to the problem that only resolved the issue for a fraction of customers suggesting that root cause analysis was below par and the fix was not tested correctly. It's possible that it was known to be only a partial fix and they decided to get it out while they worked on the rest but this also doesn't stand up for me as we were told by our long suffering BA contact on here that it was fixed, not partially fixed.
End of the world? Of course not but the lack of control, QA, ownership and communication of this issue to customers and staff should be an embarrassment. If I was involved in this I'd be hiding under my desk for a while.
*Assuming they have incident or problem management and that they actually got involved.