The weirdest things happen.
Back in the Good Old Days, KL had an unpublished RoyalWing benefit: they would block the adjacent seat on request.
I once had one of those so-called 'PROTstoelen', which also happened to be the last vacant WBC seat. Shortly after the doors closed, a lady came up the stairs to the UD, grabbed my belongings from the vacant seat, and started to look around for somewhere to stash them. Turned out she was the mom of one of the junior FAs working in coach.
After take-off the senior purser, who had obviously not been informed, came and introduced herself to "Mr. & Mrs. Rebel". Needless to say, the whole matter caused her quite some embarrassment, and the downstairs FA did not dare come visit her mom more than once, very briefly.
Johan