In terms of the "people of stature" comment there was one occasion when I was flying BRU - LHR and the exit row was occupied by two people fitting that description. When they were asked if they were willing and able to assist in an emergency they both said no. As a result they had to move, leaving the exit row empty. That meant a willing volunteer had to be sought, so I did the decent thing and moved. The requirement to have the exit rows occupied for take-off and landing does not apply here in the USA. A few years back I had the misfortune to fly Frontier from SFO to LAS. It was a lightly loaded service and I noticed that the exit rows were empty. I asked whether someone needed to sit there for take-off and was told no, that it wasn't a requirement. After departure we were told that if we wanted to spread out a bit then we could do so, but that certain rows (including the exit rows) could only be occupied upon payment of a seating surcharge!