Originally Posted by
irishguy28
The problem is not with how much the flight would earn, but where the miles end up.
As the OP is crediting the flight to FB solely for the purposes of keeping their FB miles alive, the proposed strategy is incredibly foolhardy. They need miles to post to FB and don't care about how many. But equally, they should NOT be "polluting" the booking with their Delta number in case that is where the miles post.
Completely agree. I have a FB account that I use to earn miles through my AF Amex and in the past I got a flight credited there because somehow my FB number ends up in my PNR when importing flights to my AF profile. So always better to keep the process simple.