Camping at Wal*Mart? Most folks outside the travelling retiree crowd don't know this, but many Wal*Mart stores invite RV'ers to park and spend the night in their front parking lots, free of charge. I'm embarrassed to admit that we made use of this service on three occasions during our trip, mainly on the long, mind-numbing night drives across the Great Plains states.     Paradoxically, the two best things about camping at Wal*Mart are also the two worst things about camping at Wal*Mart: First, they're usually located right on major highways, often visible from the interstate on which you may be travelling. This means they're very easy to find, but also means you must endure constant, nearby freeway noise as you sleep.     Second, most are open 24 hours. So a traveller can purchase a toothbrush, a camping pillow, and a hot burrito even at 3am, but must also tolerate nocturnal parking lot sweeping machines, late-arriving semi-trucks, and sodium vapor lights as bright as the noonday sun.     One night, in an effort to distance ourselves from all this activity at the front of the store, we parked way in the back near the loading docks and shipping containers, popped the top, and settled in. This proved to be a grave error, as we were assaulted by even more loud semis and forklifts, and I feared our boxy Vanagon would be mistaken for one of the many empty beige cargo containers, loaded onto a truck, and shipped to the seaports of Malaysia to be filled with cartons of cheap hair driers, plastic dishpans, and electric waffle irons. Postscript: Since returning from this road trip, I have learned more about the friendly, smiley-faced Wal*Mart, and no longer patronize their ubiquitous stores. While wrapping itself in the American flag, the company's predatory growth strategies harm the local economies of their own customers, and its outright and unabashed abuse of its own workers' rights—often in blatant violation of federal labor laws—make it less than the benevolent happy-shopping-land portrayed in its advertising.     In addition, Wal*Mart has also earned a deserved reputation among its own suppliers for ruthless and exploitative purchasing practices, driving some beloved American brands to the brink of bankruptcy.      To learn more about how we are shopping our way to the unemployment line, visit "The Wal-Mart You Don't Know" and Wal*Mart Watch.com.