I loathe front row on domestic flights due to need to put hand bag in overhead bin, so i specifically always pre-select 2C or 2D at time of booking (in this case in March 2022). I checked in last night, 2D assigned as expected), it was still 2D when i dropped my bag, however upon boarding app suddenly said i was in 1A (yuck - double wammy of window, my profile specifies aisle and row A)).
I asked FA if anyone was in my preferred seat and she said i could take it. Just before door closes a couple board and FA sends husband to my abandoned 1A seat, wife glares at me as she takes 2F. Caught a glimpse of her BP, bronze.
So rude to move a gold (almost Platinum) without asking because a NB didnt plan ahead and book seats together.
Seats should not change after check in unless an upgrade comes through or they ask. Thankfully FA was lovely (to me).