some jerry cans suck. they make seal kits for them, so one with a blown seal can be repaired quick and easy. not a bad thing to invest in. I carried 5 on top of my truck not vertical, not on it's side, but on it's "back". I never leaked. I got them from Sprotsman's outdoors for like $60 for 4 of them! and I also got a nozzle, a must have for the Xterra. I bought them mainly for the Rover, but since I was going into Canada into unknown territory, I felt safer having extra jugs. There are a lot of places you could potentially run out of gas on the trail, say you aren't tackling fire roads and you have a vehicle that is stuck and several vehicles are involved in winching. It's a safety thing. If it makes them feel safe out on the trail to have that extra gas, then it's a good thing.
Another potential problem is a rupture fuel line, gas tank or similar. having the extra gas may not always come in hand, but when it does, it's a lifesaver.
besides, it's always good to give to some poor hapless motorist who ran out of gas in their Honda Civic which gets like 50 MPG. Especially when it starts to go bad. :sun: