mickjoebill, I believe airlines tend to re-seat the nervous passenger where there is space to do so and the SLF in question feels safe enough after such a move...
I recall one incident retold by a c/c member where a rude and obnoxious SLF made a huge fuss about pax around them (amongst other things that this SLF had the view that he belonged in business class, not amongst the unwashed peons in Y). The c/c response was to move the person next to him to business, leaving him stewing in Y for the rest of the flight.
:-)
S.