DENVER – NOVEMBER 22: Passengers move through a main security checkpoint at the Denver International Airport on November 22, 2010 in Denver, Colorado. The TSA is bracing for heavy traffic the day before Thanksgiving, as two separate internet campaigns are promoting a “National Opt-Out Day” protest during which travelers are urged to “opt out” of the new body scanners because of concerns over privacy and possible exposure to radiation. Those passengers who refuse the scans must instead undergo an enhanced pat down by TSA agents, which could further slow down security lines on the busiest air travel day of the year. (Photo by John Moore/Getty Images)