The size of the dealer doesn't matter. It (the dye; which is a special dye, btw) goes in at the refinery or distribution terminal. There is a big difference between a distributor and a distribution terminal , i.e., a loading rack. A distribution terminal is where fuel is received from a pipeline and stored in huge tanks, typically millions of gallons, to be loaded on trucks and hauled to distributors. Unless they are a refinery or distribution terminal, they are not the ones injecting dye regardless of how big a wholesale or retail seller they are.