I've always double-checked seat assignmeents when there equipment changes but just went to check in for a flight tomorrow (I'm on a paid ticket, family on points) and our Economy Plus seats (1 Premier, 1 Associate, 1 no-status) all have changed, even though the equipment didn't. And on the one segment I was the only one with a seat assignment. All was good a month ago so not sure why the system seemingly forgot everything, but it did.... Be warned...