Just recently purchased a Mac coupler off of Ebay.  This is the device that allows you to refill the small, 1 pound bottles from a larger source. I am a bit concerned about the warning label on the bottle itself which reads:

Do not refill: Federal law prohibits transportation if refilled -- penalty up to $25,000 fine and five years imprisonment. Wow! that one heck of a warning.

How common is it for these bottles to leak after being refilled? They are meant to be disposable after all, so I doubt that the valves are very high quality. Is the risk that great, or am I just being paranoid?

Troy