Just playing devils advocate here and looking at it from the MAD pax's point of view.

He didn't get his bag so BA should do everything they can to get it back to him ASAP, even if it means sending a courier to pick it up and then bill the OP for it if they feel they need to. They shouldn't just tell him to bring it when it's convenient for him, what about what is convenient for the MAD pax?

To be honest it has always concerned me that your bags arrive in airports and just go round a belt where anyone who feels like it can pick them up.

That's why I'm always standing right by the hole in the wall where they come out of, 1st in line, whichever airport I am at.

Can't believe this is still allowed to happen in this day and age.

Airlines/airports put way too much trust in people's honesty/competence/soberness.