Reminds me of my worst ever holiday trip, when returning home after a 3 day stay in hospital, flight to GLW was delayed by 10 hours, so much that the pilots were out of time so had to divert to Gatwick. On landing, B767 went u/c (I actually watched the flap 'flapping' in the airstream!), Brittania couldn't fix so had to get another plane in. Another 6 hour delay
We were told to save time to board using our original seats, by seat row - we had been a few rows from the back, but were surprised to find we were now in the back row! yep, different cabin configuration and this one was shorter! And our flight had been full!
After much to-ing and fro-ing, they worked out that enough people had decided 6 hours at Gatwick was worse than 5 hours in the train and had gone home, so we were told to just sit anywhere.