It's really easy to get fuel from any pumps that contains some water. The water in the fuel is a big contributer to the gelling. There is a gas station that is local to me that has a problem with getting ground water into their tanks after a heavy rain storm. A friend of mine that owns a large excavation/trucking company that was getting fuel there. It caused him a huge headache to drain and flush all of his equipment and the down time was costly. Seeing that I was at that station in the fall and saw the enviormental pump truck pumping the water out of the tank, I'm guessing the problem was not fixed. This can't be the only station in the world where this has happened.
I get my fuel from a reputable heating oil company that has their own diesel pumps. Their holding tanks are above ground which will avoid any ground water flooding to get in the tanks. They aren't the cheapest around at all, but guys I know that care about their trucks and equipment buy their fuel there and say it's the best. MI've never had a problem with gelling and if I run anything but the good stuff, the tractors smoke like crazy.
As for adding lube to the fuel, newer machines don't need it because they were designed for low sulfur fuel. I use Marvel's Mystery oil in the old b7100 to combat the low sulfur. I know....it's ATF fluid.... But at least it tells you exactly how much to add to the fuel. It's not expensive, and it been around for a very long time. I even run it in my vehicles when they get over 100k, haven't had a motor blow yet. My sequoia has 170k on it now and it runs like new. Had a problem with the oil pressure sending unit getting crudded up, ran MMO in the oil, 1000 mile later the sending unit workes fine. Any lubricant added to the fuel will not help combat oil gelling.