I'm one of those people who will run across the tarmac to secure an exit row seat with easyJet and Ryanair as I'm tall. However, an increasing number of airlines charge for these seats, in which case, I don't bother. I too have been on a number of flights with no-one sitting in any of the exit row seats, and requesting a move has usually met with the response "only if you pay the fee". Wizz, in my experience, will usually let you sit there free if you are last on, but both my recent Jetstar Asia flights had all the overwing seats empty. In fact, even after take-off, they were making announcements that passengers could move there for a "nominal fee" (I don't consider 20SGD that nominal for a short flight!).