There's no need for a debate or telling anyone is wrong or otherwise!
http://science.howstuffworks.com/zoo...ans/snake1.htm
http://www.anapsid.org/sight.html

There's a few sources, although it is still a debated topic. Snakes, like ball pythons with heat sensing pits, see in infrared. So, no matter what heat is being emitted, they will see it, by that logic.

I think the best way to tell if a snake is upset by a light, is if they hide from it. Snakes are nocturnal (or crepuscular - active at dusk and dawn) and avoid bright light. They do not avoid red or black light, as far as I can tell. Mine sure don't! Which is why I have colour-changing LEDs.

Cheers!