(Source : Overland Wrangler JKU Destroyed by Fire / I warmly recommend you to click on the link and watch that stunning video from Coyote Works)
Two types of Jeepers
Which type are you?
1. Unprepared Jeepers : They are typically weekend wheelers, newcomers on the Jeep scene, or just plain idiots who rely on water/soda/beer/urine in case of fire in the engine compartment or along the drivetrain. Does it work? 1) Those fluids won't extinguish grease, oil or very hot electrical fires in an efficient manner (or not at all). 2) It's stupid to risk a thermal shock on engine parts or electonics. Especially if using cold beer cans from the cooler. 3) Water is highly electrically conductive and they risk frying vital electronics and/or blow a lot of fuses. 4) It's not a safe distance to pour water directly onto a fire or extremely hot surface. I have seen those guys and they don't even have gloves at hand. They just open the hood with their bare hands and pour whatever fluids they have in a hurry while screaming like chimpanzees.
2. Well prepared Jeepers : They are professionals driving a Jeep for a living (prospectors, geologists, engineers, hunting guides, wildfire workers, etc.) or seasoned 4x4 adventurers. In other words, they are guys that know the dangers of wandering alone in the remote wilderness. Losing their wheels could result in a huge loss of income and/or get them stranded in the middle of nowhere for days/weeks. They also know that even if they have a good offroad insurance coverage (do you?), building a replacement rig will take weeks (having to install a lift kit, extended driveshafts, gears, big brakes with twin-piston calipers, etc.).
Why is your Jeep at risk (for real)
Equipping your vehicle with an easy to reach fire extinguisher might save your (expensive) wheels one day.
1. Mechanical flaws : Most Jeepers don't drive stock Wranglers but personalized, capable and heavily modded rigs. There's room for mistakes when you start mixing things in a creative manner. Especially engine performance parts (very common here where I live). In fact, I've never seen a recent stock 4x4 vehicle destroyed by fire.
2. Electrical problems : Installing and connecting a lot of aftermarket electrical accessories (powerful ham radio, cabin controlled winch, hood led bar, 12V cooler, etc.) or a second battery is another way to "build" a fire. Some rigs look like spaceships.
3. Episodic maintenance : Preventive maintenance is quite an ordeal when you live/work in remote areas on a permanent basis or drive your Wrangler for a very long distance. And the accumulation of grease and fumes represents another important hazard.
4. Impacts : Hitting a deer or a tree tunk may cause serious internal damage. Your Jeep is at risk as soon as she starts leaking oil, gasoline, lubricant or collant. Leakage, friction and heat can be a deadly combination on the trail.
5. Overheating engine or other components : Whether you are driving a Wrangler JK/JL or another capable 4x4 vehicle (XTerra, 4Runner, Land Rover, FJ Cruiser or the new Ford Bronco), life in the wilderness will often require you to push your rig to the max while driving in the harshest climate conditions too. Overheating parts, radiator failure or leaking coolant hoses are not a possibility but a promise. Every driver eventually faces it.
Open campfire regulations
A quick note concerning open campfires : I don't know where you live but in U.S. States like Alaska, Montana, Oregon and Canadian Provinces like British Columbia, Yukon and Alberta have strict campfire regulations. One of them is to keep at least 8 litres of water + a shovel nearby the campfire AT ALL TIMES (I'm talking about open campfires, not designated spots on campsites). I know it's a pain in the ass but a violation may result in an expensive fine (ranging $300 to $3000) or even jail time (no kidding). Want to avoid it? In place of water and shovel, those regulations also allow you to use a fire extinguisher (as long as you store it at a reasonnable distance). So, a fire extinguisher will make your life easier when you stop for the night and have to build a campfire.