While President Barack Obama tries to reassure airline security passengers’ uneasiness over new, more invasive security checks at the nation’s airports, the Transportation Security Administration (TSA) is doubling-down, warning that air passengers who refuse to pass through full-body scanners or undergo manual searches may face serious legal repercussions.

Entering into the nation’s busiest annual week of air travel, the TSA is taking steps to keep the long holiday lines at airport screening moving. Any would-be flier who enters the security screening area and then refuses to undergo the designated method of inspection — whether it’s standard metal detectors, full-body scans or hands-on pat-downs — will not be allowed to fly.

Not only will violators be prohibited from leaving the premises before answering to the TSA (and possibly local law enforcement officials), they also will face fines up to $11,000 and possible arrest.

“Once a person submits to the screening process, they can not just decide to leave that process,” Sari Koshetz, a Miami regional TSA spokesperson, told the Sun Sentinel. Koshetz said these passengers would be questioned “until it is determined that they don’t pose a threat” to the public.

It’s unclear what grounds the TSA has to be able to levy fines or detainment on would-be passengers or what law one would be breaking if they refused to go through with the airport security clearance.

The American Civil Liberties Union (ACLU) is urging Americans to petition the Department of Homeland Security to change the TSA policies.

On Wednesday, TSA Administrator John Pistole testified before Congress and insisted the agency would enforce its new policies, despite the public’s complaints.

“We have to ensure that each person getting on every flight is secure,” Pistole said.