How did you find out that the last airline you used started at the back and allocated seats as customers checked-in?
Checked in and was offered 31F or equivalent in the last row next to the loo. As I didnt like the seat, I didnt proceed with the check-in and simply went through the check-in procedure at intervals watching how the seats were allocated. Eventually they reached a seat which suited my particular preferences.
I dont think the last row of seats is normally a popular choice (although it may be ideal for some people) so it seemed a little unfair on those who checked-in first.