Let them last like 3 minutes if deployed and take the place of the deployable ammo/med crate. If the player has them equipped let them turn the player into a small light source.
It should increase enemies detection toward the player on lights out maps if the player has it selected.
I was thinking about something similar. A bag of flares that takes the same slot as the med/ammo crate that yields around 10 glowsticks that can be thrown would definitely enhance the modifier. They could spawn on the map at a moderate rate additional to the other crates.
However, I would greatly favour bright glow sticks over flashing and smoking red flares.
Lights out should have idle and roamer enemies have more lights.