Originally Posted by Klm is Dead - Long Live KLM
2. If economy is overbooked but KL is not sure if everyone will show up, no one is op-upped until the last passengers start straggling in: usually backpackers running late on cheap tickets. They are handed a business class ticket as they board. Unless of course, there are still employees who have not been upgraded in which case the backpacker may be offered a denied boarding compensation.
My experiences fit this analysis. About a year and a half ago I noticed that those who were last in line to have their BPs scanned in the AMS holding pens appeared to score more op-ups. This phenomenon occurred consistently enough that it couldn't simply be a skewed demographic for the last to board i.e. this last group couldn't all be high-fare plats on every occasion. I began using this as a deliberate strategy and, apparently as a result, my KL op-up percentages increased significantly, including a recent triple translant op-up on perksaver WP award tickets!
I don't know if opups are related to check-in time, but they certainly appear to bear a relationship to sequence in final boarding, among other factors of course.
(For Steve Fenton's benefit): Long live the blue demons!
RTS