Actually, if the RADAR mode matters, BVR is the mode that I am in when I want to do this.
Specifically, in a head-on engagement, the effective range of the R-77 is much greater than the range at which I can lock up bad guys. So I am forced to fly into their lock-on range before I can fire, and I am just as likely to be blown out of the sky as the other guy.
So I would like to employ a tactic like the one I have used when flying the Superbug in Jane's F/A-18 or the Viper in Falcon 4.0 - fire an AMRAAM or two in the direction of the bad guys without RADAR lock, or even with the RADAR off if AWACS is present.
It provides a distinct advantage in that it keeps me out of the bad guys' lock-on range, and according to how Flanker is modeled, such a launch may not trigger a launch alert in the enemy plane.