http://news.zdnet.com:80/2100-9595_22-502732.html
"But U.S. military and intelligence agencies have been concerned since at least the 1980s, and maybe earlier, about what they call in official documents 'compromising emanations' from computers. The DepartmentOfDefense? operates a classified program known as Tempest, under which it is designing and acquiring technology to defend against computer-screen surveillance, according to defense contractors and ex-military officials. The government is looking for protective materials and anti-surveillance monitoring tools that can keep foreign spies from collecting stray signals from computers in defense labs or U.S. embassies."
I'd rather plead the 5th than fink on someone with one of those scanners in their pockets!