Facial recognition is spreading at cruise and airports. Should you worry about your privacy?

Say goodbye to standing in long lines clutching boarding passes and other travel documents.

Step this way, instead. Look into the camera lens and off you go.

Sound convenient? Technology companies working with travel providers and the federal government to install facial recognition systems at airports and cruise terminals hope you think so.

But privacy advocates don’t want you to become too comfortable. They worry that what we’re willing to accept for convenience sake today will soften our resistance to the idea of filling public spaces with cameras that can identify us and track our every move.

Systems that scan fingerprints or eyes aren’t as threatening as facial recognition systems, which can identify and track people with cameras installed throughout the public realm, including atop buildings, utility poles, street signs and traffic signals, privacy advocates say.

Operators of the new facial recognition systems say they take travelers’ privacy concerns seriously.

Travelers can opt out of participating in the biometric checks and proceed through their check-in by presenting traditional documents, according to the U.S. Customs and Border Protection, which is overseeing programs involving international travel..

IDEMIA says no images used by its MFace technology to speed cruise ship debarkation will be stored after trips are completed.

And the Customs and Border Protection says it retains images of U.S. citizens and exempt non-citizens no more than 12 hours after their identities are verified. Images of non-citizens can be retained up to 14 days except under certain circumstances required by law. Images that fall under those exceptions will be retained by the Department of Homeland Security “as a biometrically-confirmed arrival or departure from the United States.”

Even if travelers’ photos are deleted after they return to the U.S., federal and state agencies retain photos of citizens’ passports, visas and driver licenses in their databases that could used at any time to identify faces recorded by surveillance cameras.

That’s the capability that worries privacy advocates, such as the Electronic Frontier Foundation and American Civil Liberties Union.