One time, on a 737 LAX-HNL, a NRSA asked me to switch from my 21D full recline exit row aisle to his 20C no recline exit aisle seat. His other half was next to me in 21E. He claimed the seats were the same but luckily I knew there was a difference and declined. He wasn't pleased but tellingly, he didn't ask if 20B would switch with his other half.