Turn that stupid feature off! You die because of it! So someone has to pay the price, who ever carry's a javelin as secondary weapon and can destroy the helicopter on your team. So, should it matter if you run out ammo and automatically switches to your secondary weapon, NO! Let us do it.
Players shouldn't be penalized for this. It doesn't make it faster, if anything you get killed by it. Mostly like when you are switching at the time, enemy is near by. I'd perfer to use my knife and try it that way. That way, I don't have the weight in my hand and move freely and a lot faster.