I travelled back from HKG a couple of years ago in F, and was surprised to see everyone knew each other...apart from me.

It turned out that a Group had bought 13F seats. However, it later (40mins into the flight) transpired that there were 14 in the group, and the chap from CW was not allowed access into F.

To cut a long negotiation short, they were all rather wealthy businessmen and fancied taking the whole cabin...but I'd ruined the party!

An hour after takeoff, I'd moved into CW and was happily double counting the 'moving money' I'd been provided! BA staff knew exactly what was going on at all times, but the group were perfectly pleasant so no issues.

Shame it's never happened since!