Here is a classic sample of the use of a snooted strobe.
I wrapped my Nikon SB-800 strobe head with Cinefoil creating a snoot on my flash. By containing the spread of light, I was able to light just the subject "Mitch" without contaminating the rest of the wall.
I used an additional Nikon SB-800 with a CTB gel (cooling gel) aimed down the row of meters.
Here is a sample of the type of snoot fashioned on location. I keep several pieces of Cinefoil with me for this very purposes. Cinefoil cam also be used to flag off light, by placing a piece of foil on the side of the strobe.
I made a post some time ago before I spoke at Brooks Institute of Photography in Santa Barbara, Calif. In this post I show my small lighting kit, you might find it interesting. Hope you enjoyed the post. DT