I usually fly Star Alliance and have a lot of miles with United. But I rarely fly United... I just get United miles for my segments on AirNZ or Singapore or whoever.
My question is: couldn't you sign up with, say, 5 different frequent flier programs within the same alliance and then get credit for each of those programs whenever you flew? In other words, 5 times the miles?
When you make a reservation, do airlines/agents accept multiple frequent flier memberships? Within the same alliance?