I actually got to experience this last week due to a misconnect in IAH due to late arriving crew for my initial flight (that didn't leave IAH in time to pick us up at AUS... 2.5 hours later we finally got there with a very snarky flight attendant I wish we hadn't bothered waiting for).
Due to my misconnect I was (thankfully!) re-ticketed by the 1K desk on a flight via MIA and AA to POS... After 3 years of avoiding AA like the plague, I have to admit that their service (both on the ground and in the air), is making me question my alliance to UA...