On a recent flight, a flight attendant was checking each person's boarding pass when they sat down in the exit row, to try to proactively catch unauthorized self-upgraders.

I had never seen that before and thought it was interesting.

I believe that fight attendants enjoy a degree of autonomy when not engaged in a specific required task ( beverage service or pushing the credit card for example). Some of them have their obsessions. I recently saw one who severely obsessed over where every single carry-on went into the overhead. The older ones that look washed out are the laziest and rudest in my experience. They tend to have about ten to 15 years as a flight attendant and did not seek to move up to trainer/coach, and hang out in the plane oozing negativity. Every flight has a few people who either accidentally or intentionally sit where they don't belong, so maybe your flight attendant thinks she has a path to advancement if she can tell the manager how many such folks she intercepted. Back in the old days when Continental existed and there was this place called First Class, the FA's were supposed to bring the first class passengers complimentary drinks as soon as they boarded the plane but Continental had this one with a British accent who was very good at finding anything else to do rather than bring those drinks, and she was one of these that is a dictater about keeping the window shade down at all times, which I despise.

Ha, I wonder if we were on the same flight because this was my first (and perhaps only) time flying Frontier and the FA was checking everyone. I just assumed that’s what they did.

Sometimes an FA will take pity on a basketball-player tall person and put him in the exit row, and I've also seen it done on lighter loads for weight/balance purposes. Row 13 is also very much a favorite for deadhead crew.

All of which doesn't preclude the possibility they've gotten complaints from those who actually paid for the upgrade and HQ could have sent out a memo saying to do it a lot less. Part of the paid experience is to hope for an empty middle seat (if flying solo), so if they put a passenger of size there free it can really degrade the experience.

And I know this is 100% anecdotal, but it seems with the elite upgrades in the 24-hour window that rows 1-3 always seem more popular than the exit. I know those with kids or disabilities can't choose the exit row, but even so I've often had a much easier time getting that than the first three. It's especially relevant on transcons or near-transcons where more people are willing to pay and the elite upgrades appear more competitive (snooze ya lose).

The downside with the exit row is that some people appear to think it can help if they're wider. All they'll get for that is an immovable armrest, most likely. It helps with height but not with width.

I wish they checked more often.

One flight I had this guy try to self upgrade and flight attendant notice him immediately. He then tried to ask if he could sit there. FA told him he could if he paid the upgrade fee. He said he would and then when FA came back, he didn't want to pay and said "can I just sit here for takeoff?". FA told him no and told him to go to his assigned seat.

I see more likely to get an empty middle next to me in exit row. Row 1-3 often get filled for whatever reason. I've seen them out a lap baby in row 3, theyve had disabled people there and I think when plane gets full, they fill the exit rows last.

That being said, I posted a year ago about this overzealous FA out of Jamaica. I was in the window seat and this guy was ticketed in the aisle. He tried to move over to the aisle exit row in the otherside bc no one was in that row and this surly FA told him to go back to assigned seat. She was really nasty in the way she said it. I even made a comment to the guy when he was forced to move back.

I had never heard of someone not being allowed to move over like that.