Wal-Mart

There is little sign that consumers are yet cutting back as a result of higher oil prices. Lex: Wal-Mart:

"At a time like this, it is nice when retailers manage to avoid nasty surprises. That is especially so when it comes to Wal-Mart, which remains more exposed than most to price conscious US shoppers feeling the squeeze from higher petrol prices. For now, however, rising fuel costs seem to have reassuringly little impact on either revenues or profitability. "

I guess the main evidence would come from lower sales at Wal-Mart or even higher sales if more people were pushed towards the cheapest items.