Quote from sgt.flippy :

I think you just have to keep your racing line, and if the car behind is a lot faster, just slow bit down, use your indicators to let the guy know where to pass. I thought this thread was about the blue flag being there for too long. I have no trouble when I get a blue flag, it just gets annoying if the guy just doesn't pass me, or it takes a long time and it keeps telling me I got a blue flag.

IF he/she even manages to come into strike-distance before making a mistake...
But once there i've ablosutely no problem in providing easy pass opportunies.