@Bushwack:
Spray painting for chopper landing, muahaha. Thats definitely not what I meant.
I meant to have some kind of military spraying thing (no rattle, small size), for painting on walls.
I know it sounds stupid, but it is just an idea, but for some kind of special forces missions, also regular army thing, in a destroyed village. A soldier can mark a wall of a building to signalize to mates that this area was cleared, or something (flare works limitted time and is to visible).
Or to mark areas so you know a path if it is a complex jungle map where buildings and trees look all the same.
Maybe you can signalize to a sniper, that he has to search for a red cross on a wall of a house to cover this building, when a recon, saw enemies there. Cuz it's to unprecise to explain which building, when they are many.
Not a big thing, was just a thought.