Stupid people in staging lanes on saturday!!

NOS is non flammable, it is use as an oxidizer. Meaning it is used to help combustion. If you have a fire NOS would help it burn hotter and faster. The only explosion from heating the bottle would be from over pressuring the bottle from expansion due to uncontrolled heat source(still not good). It is an idiotic thing to do, I wouldn't apply flame to any pressurized bottle even an inert gas like CO2. As stated there is bottle warmers available so this is another classic example of using the wrong tool for the job.