Colin is right. We've had the same discussion over at the BA board many times. The bottom line is that the whole point of an inflexible fare is that it's inflexible. If the rules were bent, over time, people would learn about it and the airline would no longer sell flexible tickets, and the revenue loss would be tremendous. There is really no middle road option here for an airline, i.e. let's bend the rules just this once because it's a good idea! That's something a 20-100 person company can do, not companies the size of BMI or BA.