So I recently had the pleasure of experiencing these mystery seat changes. Nothing too crazy but thought it would be interesting to share and get your take on what might have happened.

My family and I recently flew from ATL to EWR. Originally when I booked the flight I had selected 9D and 9E for my wife and 5yo daughter, and 9F and 10F for my 7yo son and myself. So my wife and kids would be in 1 row and I would sit behind them in a window seat. This is our preferred seating arrangement when we travel on aircraft that is 3-3 in economy.

When I checked us all in via the app on 4/18 I noticed that my wife and daughter still had the same seats but somehow my son and I had been moved to 11E and 11F. Thankfully the previous seats were still open and I was able to move my son and myself back to 9F and 10F respectively. I figured it was some type of one time error in the system and let it go.

Next day when we were about to board the flight, imagine my consternation when I found that somehow my son and I had been moved back again to 11E and 11F. I checked with the gate agents and they were unable to help since the flight was full, however they said it may have been due to us being on 2 different PNRs and some effort being made to keep child and adult together. That the system or whoever made the change on the United side were unaware that my wife and daughter were in 9D and 9E and automatically moved my son and I back to a row where there were 2 seats next to each other.

I am not sure if this is some type of automated system that tries to rearrange seating in this fashion or someone at United reservations or operations executes these seat changes. In the past the only times this has happened was when there was an aircraft change or if bulkhead seats were needed for the disabled and neither was the case this time. It was not a big problem as my son and I were seated next to each other, however this was not my family's preferred seating arrangement. I guess from now on I need to babysit all our reservations...