Would you like a dart you could shoot on any enemies, and if this dart hit one, it will stick on it for a while revealing everyone around the target? Like the parasite spell from the zerg queen unit in starcraft 1. And you could destroy that snitch dart by shooting at it (you'll need to be a bit accurate to not team kill the target)
It's an interesting idea no doubt but probably impractical to implement. You are describing a regular dart that would move with the character or vehicle. If this were enacted, though, I would shoot my flash to get free recon.
If C4 can be stuck at some point on players weapons it may be possible to extend this to the bodies weapons Also using it on your own vehicle would give your own position!
C4, sticky nades, av nades. all of em stick so it shouldn't be so hard to implement it into the recon dart.