Good for an airline enforcing the carry on rules.
But United is horrible, I will never fly them again anyway. Got stuck in a NEWish plane, the A320 SLIM version, on a flight from LAX to Newark, NJ, non-stop, 2 weeks ago. Over 5 hours.
IF you see you are booking a seat on one of these planes, switch flights! Or switch airlines! The worst flight of my LIFE. The seat pockets are so small, you could not even fit a book in them, much less a water bottle. 1" armrests between the narrow seats, so you are skin to skin with your seat mates (who may be strangers). So uncomfortable, and I am used to coach.
I don't think it is ALL A320s, just the slim version I got stuck on
.. (and the irony is, the plane looks so new when you first board, you are like, hey, NICE. Then you realize, I can't fit my water bottle in here
then you sit, and you realize, this is NOT good.)