I was first to board an ORD-LGA flight a little over a year ago. After I was seated in F, a veteran came on with a wheelchair and who was missing a leg. I insisted that he take my seat. I told him it would be easier for him to sit in 1D than his Y seat. He said thanks but no thanks, but he really appreciated the gesture. I told him I fly in F all the time and this was no big whoop. I insisted again, and he still refused. The FA heard me talk to him and wanted to know what the deal was, since she really didn't hear the conversation. I told her what I attempted to do. She went back and told him it would be okay for him do it. He still refused.
She was really touched by my offer of kindness. I think I had the best service ever on that flight.
I really wanted to give the vet the seat.