WEP flaws have cost retailers money before. Last year, Albert Gonzalez was convicted of stealing more than 130 million credit card numbers. He used various methods, but got many of the card numbers by wardriving retailers including TJX Companies, OfficeMax and Barnes & Noble. Once he found a vulnerable network, he would hack in and install credit card-stealing programs.

Many big retailers have beefed up security since 2008, when Gonzalez was hacking, but small companies are often at risk. In its annual Data Breach Investigations Report earlier this week, Verizon said criminals are as it becomes harder to steal financial data from big companies.

Police impounded the Mercedes last October after arresting its owner for allegedly using stolen gift cards at a local wine bar. In the car they found a range-boosting antenna and a Wi-Fi-enabled laptop with a passenger-seat mount, so that it could be used while driving. Except for the front, all windows in the car were heavily tinted, making it difficult to see what was going on inside.

Investigators had been tracking the black Mercedes since at least February 2010, Hansen said in a court filing requesting permission to seize the car. A spokeswoman with the U.S. Department of Justice would not say whether charges had been brought against any of the suspects.

The gang is thought to have stolen more than US$750,000 worth of items, according to the Seattle Post Intelligencer, which .