On the first point, that's a common complaint. There are dozens of threads about it. But the policy works well for those of us who are flying BA half a dozen times or more a year (sometimes many more), and for better or worse BA has decided to have a policy that treats the frequent flyers better and the infrequent flyers less well.

And let's face it, this policy has now been in place for something like a decade.

I'm not sure that it would have made any difference if they had booked on the same PNR, but had chosen not pay for seats. A busy flight is a busy flight, and if so many people have already chosen their seats before check-in opens that there aren't any pairs left, then there simply aren't any pairs left.