In an effort to inform businesses about lax security on their wireless networks, agents from the Secret Service have been wandering the streets of Washington, D.C., looking for unprotected wireless networks. Using a laptop, a wireless card, and one of several antennae — including one made from a Pringles can — agents drive through city streets, checking for access to networks.

Hackers did a similar exercise as part of a competition at the DefCon conference held in Las Vegas this past July, with prizes given for the most networks captured.

Chris McFarland of the Secret Service’s Electronic Crimes Task Force said that “people can wreak havoc with [unprotected wireless] systems.” Special Agent Wayne Peterson said that on a recent trip down one street, they found more than 20 networks, many without any security at all.