Before I moved here I lived in the mountains of Calif. and worked on small engines for our local hardware store. I was also on the fire department there. For small engines or riding lawn mowers A baffel was just A screen on the muffler outlet, they seemed to work but mowers like mine tended to back fire when you turned them off and they were useless then. I have put out A fire or two from that.
Our RC club had one rule, NO GAS ENGINES during fire season and it was inforced, didn't need to be because everyone knew the danger.
I have only seen one fire started by A glow engine, it was on A soaked start up stand and the pilot let the fuel flow from the muffler when filling. On start up it sort of back fired and fired up the fuel. If it wasn't for the old carpet on the bench top no one would have noticed.
The glow engine/plane really is no problem but as mentioned the battery/switch or some of the new batteries do not take to impact too well.
My old mountain field never had A problem and we had some very hard crashes in the tall dry brush. I don't think I would worry about it at all.
OLY hit it right on too. During Deer season we put out A bunch of fires started by auto converters and tall weeds. Take A peek some night at that thing after driving for A while, they can be glowing!!!
For A fun story ask me about our old CROWN fire engine that backfired when you changed gears!!!