I'm all for "cheating the system" with their past and now Elliott boarding schemes / fees but saving an "real" exit row is just arrogance, especially for some idiot (like me over 10 years) who paid for a BS A01 ticket only to board late through no fault of my own (late connections).
Many times I've snagged the infinity seat and asked people to keep moving because I was saving a seat for my daughter or GF but there were nothing special about the remaining middle or aisle seats so no one cared. Or the love seat for that matter. Many, many years ago an FA said seat saving was ok but not in the exit row. And that px couldn't move up during the break since they were reserved for BS px. Which would have made sense but of course not documented hence another FA corrected her.