Like Brian said, local marinas don't want you gassing but they really don't want you to gas at the dock and blow up the place.
My marina did not sell gas, but I came down to the boat 204C with five x 6 gallon poly cans and lined then up on the walkaround, fit perfectly, tied the last one off with a rope.
Then I would gas up after pulling out into the channel well away from marina and wakes, then came back to the dock with 5 empty cans end of day, stored up on walkaround.
The owners talked to me but had nothing since I didn't gas at dock, which is prohibited. And they didn't sell gas. It is not illegal to cary portable gas cans in my car or into marina in my car or into boat from my car if approved for such use, as mine were 6 gallon wedcos.
Need less to say, others though I was gassing at dock and they would do the same but would actually gas at dock, back to car with cans. Owners never liked me much but kept an eye on me whenever I came to boat with the poly cans.
Red is supposed to be for gasoine as I believe a different color is for diesel (yellow?) as a different color is for fresh water (blue?).
If you go back to gas one one day just rinse a little gas first. I used the 6 gallon poly cans also for buying OMC bulk 2 cycle oil at dealer. Then transfer to several 1 gallon 2 cycle oil containers reused.