While waiting in check out line the other week in Publix, I happened to notice two guys looking at stuff on a display near the check out. The entire display appeared to be gift cards for nearly every national chain and major company. They have every gift card from Best Buy to TGI Friday's. It wouldn't be surprising that they have gas company cards too.
I hear people talking about boycotting BP and laugh a little inside at the idea of really being able to do that. Even if you don't fill YOUR tank at BP, you are still supporting BP when you buy produce at a grocery store, which gets their deliveries made by a truck which uses BP gas, and from the farmer who may buy their diesel fuel for their tractors from BP. If it isn't coming from BP, it may come from another oil company who buys wholesale from BP.
What are the reasonable alternatives? Exxon? Citgo? Chevron? If you really want to boycott BP, it might be best done by living a self-sustaining life in the woods.