Three years ago, a Connecticut-based technology company called Walker Digital developed an innovative system -- named US HomeGuard -- that promised to place thousands of the country's critical infrastructure sites under round-the-clock surveillance, economically and quickly. Walker offered the system to the government for $1. The company never planned to make a cent on HomeGuard commercially. It never even expected to recoup the several million dollars it spent on the effort. "We did that as good citizens," says Jay Walker, the company's chairman. "We just don't focus on the dollar amount." Offered HomeGuard on a silver platter, the government did...