Wal-Mart is worried about rising gas prices, as well they should be. Most of their stores are completely car dependent and as gas prices rise it becomes less attractive to motor to a store in a paved over corn field to do some recreational shopping and savor the free air conditioning.
Also, we all know the people who feel the gas price (and rising interest rates) squeeze first fit the profile of typical Wal-Mart shoppers and employees-- hard working people who are paid shit, are treated like shit, and operate with no financial safety net at all; people who rely on hope and day dreams fueled by lottery winning fantasies to maintain some sanity and remain compliant participants in a brutally unfair society.
Tough shit Wal-Mart. Maybe you should offer free fill ups.