Just been upgraded from eco to business flying VIE - DXB.

Received my economy seat as normal at check-in, then upgraded at the entrance to gate. Asked if I was travelling alone (which I was) and if Dubai was my final destination (which it was).

I do most of my travel with OS and LH so only a blue emirates card holder, it appeared however that i had been preselected for the upgrade so i guess blue is enough.