This sad thread has been 'rolling' downhill since the get go. Now hear this, rather picture this. A dozen or so yrs. ago - we parked in Acapulco, Mx. for the winter. Best place to get our tanks refilled was about 1/2 hr. drive north. Dumb me watched as the Mx. tech. removed part of the valve prior to refill. I don't speak the lingo but, understood that was needed for some bumb reason; i.e. purge.
Months later in Texas, the dude there said I needed an valve upgrade to comply with their (Tx.) regs. X dollars later, I was good to go, with a full tank.
The new upgrades plus date were stamped on the top of tank near the handle(s).
Now, later still back in Canada - local refill guy looked puzzled and said he could not refill due to the markings (from Tx. USA) which he could not 'comprendee' - whatever.
Lessons learnt - go at night to a busy service station - where, tank refills are done, with nothing more then, pay . . . . and have a good nite, sir. BB
p.s. So much for NAFTA!