And there I was, innocently thinking that the "thieving" referred to in the OP was the charge for the second bag, which would normally have been carried as cabin baggage but was required by new regulations to be put into the hold.
For BA to charge extra in those circumstances is a bit rich. I'm not sure that I would quite call it "thieving", myself, but I understand where the OP is coming from. I wish that BA had made the leniency/concession clearer at the time.