For anyone who is concerned about this issue, you can install the factory heavy duty skid plate for the tank and the OE trailer hitch even if you don't tow. Both of these, shield that tank very well. The factory hitch sits between the bumper and the tank and the skid protects it from low cars under-riding the bumper. The factory tank skid (the standard on on the WJ is just a brush guard, the optional one is much thicker) on both the WJ and ZJs are strong enough to lift the Jeep from with a floor jack. I put the OE hitch and skid on my ZJ 15 years ago to make it as safe as I could. There's nothing wrong with that, in fact that should have been standard on vehicles with a rear mounted tank.
2007 WK Limited Hemi QDII
1998 ZJ Laredo 4.0 Selectrac