I have not tried the following:
1) Filling the gas canister at a water pump and drinking out of it (works, does not cause illness)
2) Collecting rainwater with the gas can and trying to fill up a vehicle. I suppose this would be a definitive test, which I will attempt later today,
3) Filling a canteen or water bottle with gasoline, emptying it, and refilling with water and drinking.
4) Fill the gas canister with water and placing it in a fire.