I figure a head-on pass is likely mutual suicide. So when I see some clown coming straight at my nose, I quickly assess the tactical value of our positions and decide if I'm willing to trade my plane for his.
For instance, if I'm defending a base and we still have FHs up and it'll take me one minute to regain my current position, but the enemy is far from home and it'll take him ten to regain his, I'll happily make the trade.
It takes two to head-on. Anyone who doesn't like it shouldn't point his nose at mine.