Neat tricks.

I've been tempted to order a couple of these just to see how they work. If you stashed a bike as a specific bug out vehicle, it could be invaluable:

http://www.stopaflat.com/toobz.html

Seems similar to, though more civilized, the idea behind stuffing newspaper in the tire. They must be tight though. I imagine wrenching the tire over the rim is a real chore. I'm sure they don't roll as well as a good tire inflated to 100psi but sometimes that's not what you want anyhow.

You can also get tape to put between the tire and the tube which is puncture resistant. Most people I know don't like them because they add mass to the tire...but on 20" tires I bet you'd never notice.