In CTF, the user can throw the Flare in the flag room, run in, and collect the flag (if the user can take the flag and run away in the right direction).
When deployed in narrow corridors, it is very useful for blinding everyone in a nearby vicinity.
If used in small areas in Infection, it is good for making quick escapes.
Throwing the Flare at the sniper makes it nearly impossible to see you, allowing for a quick and easy dispatch.
A simple but annoying tactic in Forge is to set the Flare to respawn instantly after being picked up. The player can then continue to throw Flares in the same place and create a miniature sun. The standard extreme light of the Flare is amplified and the entire screen goes completely white, with the exception of the motion tracker and HUD. It can be used to simply annoy other players, or if used with a partner, a sniping asset. Silhouettes of the players in the Flare's radius are visible, and for a sniper located farther away, it is an easy way to rack up kills. However, the Flare-dropper can also be killed by accident by the sniper, thus ending the "flashlight of death".