It not in their terms of trading and I don’t believe that they have ever complied with this !
Even the major carriers play lip service these days
Long gone the days BA might put you on a Pan Am 727 to Berlin 😉
Indeed the LCC terms and conditions and indeed many of the legacies budget fare options explicitly state the ticket is NOT an obligation of carriage. The fully flexible economy and business fares only provide that obligation.
And it’s not new Apex fares of old also excluded the obligation of carriage and cover !
Now a legal case might indeed be necessary to test the cases however that’s not going to change thing on the ground right now so to speak
We also need clarity on the full UK rules post B do we not