I don’t know how it works for EBGs, especially these days that there are a lot of matched ones, but as EBD I’ve had at least 20 Go-Plus upgrades due to over booking in a year alone

The key is that you have to live somewhere that is very poorly served and there’s always more passengers than seats and I don’t know is it because of lack of aircraft or just not being a profitable destination for SAS, but Helsinki is like that and every other time that Go is fully booked, Ive bumped into Plus an hour beforehand! It happens more HEL-ARN-HEL but occasionally HEL-CPH-HEL.