I agree that we all need to be aware of dangers involved in propane usage and transportation. I received this very warning in an email and promptly forwarded to many of my friends. One person responded with this link to Snopes.com, the urban legend site.
snopes.com: Methamphetamine and Propane Tanks
It basically says, while the danger is real, the chance that a meth cook is going to take a propane tank back to Walmart, or any other place of exchange, for that matter, when he is done, is pretty far fetched. These tanks are under pretty scrutinized federal guidelines. Even if a crackhead did steal a propane tank, he is not interested in a tank full of propane. He wants the anhydrous ammonia he can fill it with. Even if he did take it back to Walmart, the chance it would get back into circulation is not real high. The crackhead has a better chance of blowing himself up first LOL. Bottom line is, We all need to be wary, and if you suspect illicit use of a propane tank, report it to the authorities. If you have you own tank refilled rather than do the exchange deal, you have nothing to worry about.
That'll be 2 cents please!