On Fri, 27 Sep 2013 05:01:02 -0700, bob haller wrote:

http://www.ncagr.gov/standard/LP/LPg....htm#Delivery5

Nice find!
That North Carolina web site says what I believe California does also:

Q: Why wont another propane company fill the tank at my house?
A: (North Carolina) state law prohibits one company from filling a tank
belonging to another company. You may shop around for the best price
(of propane) if you own the tank yourself, and that is the return
you get for your investment of buying a tank.

It seems to be the same out here.

The propane company will gladly fill their tank or my tank, but not someone
elses' tank.