When did the OP book the flight anyway? Months ago, the day before this thread?
Or a Bronze card holder who went to reserve seats at T-7?

In my opinion, being seat shifted perhaps months in advance wouldn't be that bad as it would still give a good range of options, but if someone comes along and books at say T-48, then I would probably be rather miffed especially if I've had a certain seat reserved for up to a year in advance.
At this late stage, you'll probably find most seats are taken and a few undesirable ones left such as middle against a toilet wall remain. Not going to great for someone if they go to check-in on Friday or at the airport on Saturday and find they've been shifted, without any warning from 26C with their family members back to 70e or something.....