A certain large UK airline recently refurbished the cabins of its narrow-body fleet. A captain on his first flight in a 'new' aircraft noticed that, after the passengers had left, the seat belts on the RHS of the aisle were all dangling 'buckle-side down' he noticed the cleaners knocking into them with their shins and indicating their annoyance. As he had never noticed this feature in a pre-refurbished cabin, he assumed that the belts had been incorrectly installed. He therefore contacted engineering, who told him that this installation was, in fact, correct. I'm not sure if the seatbelt design or length had changed.
Confusingly, I've noticed since then that some 'new' cabins have the belts installed the other way around!