Janet Napolitano

With transportation security officers increasingly under fire from some quarters, Homeland Security Secretary Janet Napolitano on Tuesday sent an email to all Transportation Security Administration employees, saying she wanted to “take a moment to personally thank you for the work you are doing to keep the traveling public safe.”

“The threats we face in the aviation sector are real and evolving, and we are meeting them with a strong and dynamic response,” she said. “Serving on the front lines, you ensure safe and efficient travel for the millions of people who rely on our aviation system every day.”

This comes on the eve of one of the year’s busiest travel days and as critics of new TSA security measures call on those traveling the day before Thanksgiving to refuse full-body imaging, which would force TSA agents across the country to give pat-downs and, the critics say, would let Americans “see for themselves how the TSA treats law-abiding citizens.”

“The government should not have the ability to virtually strip search anyone it wants without cause,” says the website OptOutDay.com. “We do not believe the government has a right to see you naked or aggressively touch you just because you bought an airline ticket.”

In her email Tuesday, Napolitano insisted that “time and again, the men and women of TSA have demonstrated poise and professionalism.”

“Travelers and the public realize that your job is difficult and demanding,” she said. “This holiday season, I am confident you will again demonstrate your commitment to ensuring the safety of the traveling public to everyone who passes through an airport security checkpoint.”

She said that as the threats against the United States “continue to evolve, the nation continues to count on you as their last line of defense against terrorism and rely upon you to execute your mission efficiently, professionally and courteously.”

“You have continued to rise to the occasion, and for that, I and all Americans, are grateful,” she said. “Thank you for the service you provide to our country.”

Nevertheless, several websites are calling for a national “Opt Out Day” on Nov. 24, insisting many Americans “only fly around the holidays and may not be aware of the security changes.”

“The government should not have the ability to virtually strip search anyone it wants without cause,” says the website OptOutDay.com. “We do not believe the government has a right to see you naked or aggressively touch you just because you bought an airline ticket. … Once people are made aware of what is happening, they may have reservations about the new virtual strip searches and enhanced pat downs — especially for their children or spouse or other loved one.”

During a press conference last week, Napolitano said she “really regrets” such calls to “opt out” of certain screenings, insisting TSA and her department act responsibly “with good intelligence, with risk-based analysis.”

She said “everybody has a role to play” in preventing terrorism “and if people don’t want to play that role, if they want to travel by some other means, of course that’s their right.”

There are currently hundreds of advanced imaging technology units at airports around the United States. According to TSA and DHS, an officer located away from the security line views a slightly blurred, X-ray-like image of a passenger, but the officer does not see the passenger. The image cannot be stored, transmitted or printed, and is deleted immediately once viewed, authorities have said.

According to recent polls, the vast majority of Americans — as much as 80 percent — approve of using advanced imaging units at airports.