Don't forget that OLCI and especially PYOBP makes it a LOT harder now for BA to know how many empty seats there will be.

In the old days, if you hadn't checked in at a desk in the airport 60 minutes before then there was a decent chance you weren't coming and standby pax could be accommodated.

Today, however, if I have OLCI'd and PYOBP'd from the comfort of my home or office 24 hours before, BA has to assume I am coming and leave my seat free. BA doesn't know until the split second it closes the gate that I am not in the airport and intending to travel. At that point it is too late to reallocate my seat.