I will approach and set up as usual, if I am asked to back off, then I will do so - otherwise - I am going to join in. The opponent has the option to either fight 2 v 1 (and win for glory) or run (for survival) - - there have been plenty of situations where I have joined into an on going 1v1 only to find that the enemy start to multiply pertty quickly. If people really want a 1v1, then go to the TA and do all the 1v1s you want - but in MA - whether you like it or not - its for country. I would rather free that pilot up and get on with pressing or defending, too many people playing around doing 1v1s and such take away from the overal MA experience and that persons slot (since MA is often full) should be opened.
But if asked, I will respect the pilot and back away.