This is just idiotic and terrible customer experience.

Just got off an MH flight, had exit row (got it in advance thanks to equipment swap from A330 to B737). The couple next to me even decided to change away from the exit row, so clearly they didn't want to be there in the first place. On the row behind, at least one person decided to move away too. If these seat assignments were free for the people who they should be free for, who knows, you might even avoid that kind of reshuffling once onboard. Before OLCI, I was the only one at any of the exit rows too, so it's unlikely they collected any extra revenue from these seat assignments.