i like the comment from the guy who said No2's not flammable....... riiiiiiiiight. lol
he is right, sort of..at room temperature n2o is not flammable. it's only under the high temps and pressures present in the combustion chamber that the nitrous oxide breaks down to it's nitrogen and oxygen components. the oxygen will then definitely burn.

the phase change from liquid to gas in the bottle and it's expansion as it exits the solenoids helps to cool the combustion charge somewhat. it's pretty cool in a nerd sorta way.
that being said i'm sure if someone sticks a torch in front a nitrous bottle it will probably burn. but at room temps it is nowhere near as volatile as gasoline.