Boston is one of only two cities in which the new touchy-feely frisking is being implemented as a test before a planned national rollout. The other is Las Vegas.

“We’re all for good effective security measures,” American Civil Liberties Union of Massachusetts spokesman Christopher Ott said. “But, in general, we’re concerned about this seemingly constant erosion of privacy, and we wonder whether or not it’s really going to be effective.

“Accepting these kinds of searches may keep people safer in some situations, but not in every situation, and we’re encouraging people to stop and think about what is the right balance between privacy and security,” Ott said.

A TSA spokeswoman yesterday confirmed the switch to what the agency calls an “enhanced patdown.”