I once suggest to a PAX that I noticed two open seats and that he might like to move to another row with the open seats. He said that he was comfortable in his seat. I said no problem and remark that I made suggestion only so we could all be more comfortable with a little extra room. He looked at me, paused, smiled and as he understood my suggestion. We went from 1-3 to 2-2 seating for the flight.