Data points:
- Sept: upgraded from Y to PE (overbooked Y)
- June: upgraded from Y to F (Y at 60-70%). I was travelling with a friend who was in paid F and who was designated by EK as a VIP but no status. Separate PNRs but we checked in together and entered the lounge together so possibly someone noticed we were travelling together? I was surprised by the upgrade and the agent in the lounge could not explain it but I only asked in passing.