http://www.huffingtonpost.com/jay-stanley/full-body-scanners-from-a_b_694466.html From the site: “Unless they have probable cause to search a specific vehicle, government agencies had better not be roaming U.S. streets conducting backscatter X-ray scans of vehicles and their occupants (much less pedestrians, cyclists, etc.) without their knowledge or consent. The Constitution may have taken a battering in recent years, but on this point it remains clear.”