[TimG]

To not purchase fuel on May 15th is the equivalent of telling your parents you'll "hold your breath" when you were a kid. The demand will be there the day before and after the 15th. Some businesses are required to fill up every day, say for a trucking company or the guy hauling your '69 Camaro from Georgia to Arizona. What if he decides not to purchase fuel on the 15th and parks his rig in Florida for the day? Many retailers are independent companies that earn five to 10 cents per gallon. Someone pointed out that they make their profit on the inside sales including beer and cigarettes. This is true. If you want to hurt them, don't buy their inside stuff, they break even on the fuel at best after delivery costs and payroll. Look at what Wal-Mart sells their fuel for and you'll see the price many retailers pay wholesale for their fuel. Wal-Mart will use the fuel portion of their business as a loss leader, or to draw customers in or for the cash flow.
If you buy 20 gallons of fuel at a five cent per gallon profit, the retailer makes $1.00. If you buy a 12 pack, they may make three times that. The wholesaler (the big guys) make about 10 cents per gallon profit, we pay nearly 50 cents per gallon in taxes here in Texas, so the Federal and State Government makes five times what the wholesaler makes and does nothing. They don't find, refine, sell, or store the product, they just tax it. A wholesaler may make 10 cents per gallon and a retailer may make eight cents per gallon. If the retailer and wholesaler are the same entity (like all the Exxon stores in Austin) they may make 15 to 20 cents per gallon. If they gave it away for no profit, would the 20 cents make a big difference? All the fuel sold in Austin comes in from one pipeline from Houston, TX. The terminal is owned by Koch/Flinthills Marketing and it is piped in and the additives are added at the terminal to differentiate all the different brands. Unbranded fuel has no additives added to it. The fuel is sold on an exchange basis many times, it's all the same product regardless of if it is Shell, BP, Conoco, Exxon, Chevron or whatever. The additives distinguish the fuel form the competition.
It would not matter if you boycott a specific brand, if Exxon doesn't sell a drop, they sell their excess to BP and they sell it. Exxon makes their margin and you can't really make them feel the squeeze.
I don't know about you, but if need fuel on the 15th, I'll buy it.