One thing I wondered about was the incremental revenue BA expects to get from these changes.

If, as they say, 98% of pax will be within the new limits, then no more than 8 pax on a flight will be charged, ie less than GBP1000 per longhaul flight (and much less for shorthaul). This ignores passengers connecting, as the charge is per one-way trip not per flight. So if assume half pax connect 2 flights and other half are O&D the extra revenue is less than GBP750. BA only needs to have a couple of pax book on another airline and they are losing net revenue.

I appreciate this ignores any efficiency savings (which must surely be negative at least initially as pax argue the toss with check in), but it seems a risky move in terms of revenue at least.