What do the motion sensors (balls) do for the Recon Kit?
If you throw one of the motion sensors out, it will cause any of the enemy players to appear on your teams minimap within the range of the sensor. Very good for a defending sniper to use to help out with crate defense. Also used in counter sniping when an enemy sniper has set up behind or in your current base, or when you need to make sure no one is sneaking up on you.