I have blue flag msg on my F1 key. I use it all the time.... when on grid, before race goes green, and I'll gladly keep using it no matter what anyone says
But strangely enough I rarely use it while racing.
I understand why some ppl use the message - I remember my own early days with LFS - I was aware of blue flag and what it meant, and tried to drive properly. But still had complaints - Back then I mostly drove in the FOX and later realized that it was because I wasn't interpreting the distance while looking at the rear view mirrors correctly - I thought they were too far away, while the about-to-lap car was actually up my ass.. sort of :P
Sometimes I also had issues with wth. I should do, where to go - You can't expect every single back marker to be fully prepared for every situation.
But on the other hand, some lapping drivers are indeed too eager with the BF messages - some seems to hit the key as soon a back marker is in sight... sort of :|
But hitting the BF key isn't pointless IMO, since the big LFS text does appear in "various" times - depending on the car it car appear it can appear too soon.. So my guess is that some drivers may be "meh, I'll just wait a bit.. he's too far away" - some even think tthat the lapper isn't fast enough - I used to think this too, but failed to recognize that of cause he isn't faster when I'm slowing him down