GoForSmoke:
IR reflectivity, you might be able to test with a webcam, but might have to modify it.
I've read that mobile [cell] phone cameras will also do that, without modification.
Talking of night scene filming, there's a model railway here (Pendon, Oxfordshire, UK) part of which has a model man leaning against an outhouse, smoking a cigarette. When they dim the lights for the night scene you can see the end of the cigarette glowing. Now THAT'S dedication to modelling!