I did a stint for three years as a wildland hotshot firefighter. Yes, firefighters will treat and look at you with total contempt mostly because you are a perceived liability. If you had to, make sure you buy the correct nomex fire redardant shirt and pants. Also, if you do not have an "emergency shelter" you might get shut out. Fires and winds can change in a micro-second.
That being said, my 1st commercial photo was for the inside page of a Wildland Firefighting rag. LOL