I've seen (and participated in) some excellent discussions on how the recon decoy unlock works and what it is useful for. However, I would like to draw attention to a use of it that many may not know about.

It has been established by trial and error that the effective radius of coverage by the decoy is about 60m in each direction, making it useful in small and urban maps where view distances are relatively small and there is a lot of fighting in close-quarters.

However, once you leave that radius, you become visible again. Oh no, the decoy is useless thereafter, right?

NOPE!

Imagine this:

You are a recon equipped with the Lambert and camo/decoy. Your squadleader wants to mount an assault on a flag held by a strong squad. What can you do to even the odds?

You take your active camo, and run in an area on the opposite side from your planned assault, that you are sure an enemy IDS or Q-spot detects you. Then hit up that active camo, and run just out of range. Deploy your decoy into range, and then slip away. If you did it right, it looks like a Squadleader just ran past, and had a squadmember spawn on him before moving out of range. Guess what that squad will do? It will send anywhere from 2 to the whole squad to take care of those "contacts". In the meantime, your squad, which has been waiting patiently, can run in and cap the flag before the enemy even knows what happened. It doesn't matter that you, as the recon, appear as another blip on their radar. It's the decoy that does the work for you, giving the appearance of a hostile that will provide the distraction necessary to overwhelm a superior force.

In this case, you are using the decoy not as a way to hide, but rather a way to clone yourself and confuse the enemy. So remember, just because you're out of the range of the decoy doesn't mean it ceases to be useful.