Alexander Hernaez, an attorney with Fox Rothschild LLP in San Francisco, and a Clear customer, said he was personally upset by the decision to shut the service down because it had made flying out of the city much easier.

About two months ago he signed up for a two-year Clear membership after being convinced by the company to do so, he said. "It did make sense to me that they would try to lock in people for longer terms," Hernaez said.

Hernaez said he hopes that the operators of Clear "will follow their obligations and safeguard personal data especially the biometrics data." Hernaez said that while he is not overly concerned about the data being misused, he would like to see it protected all the same.

"I wish there was some communication by the company," about its plans beforehand, he said. "If anything left a bad taste, it was the nocturnal notice [from Verified Identity announcing the closure,]" he said.

Another customer, Jason Mendelson, co-founder of a Boulder, Colo.-based venture capital firm called the Foundry Group, told by e-mail that at this point he would like Verified identity "to assure me" that all personal identity information will be destroyed. "That's really the only reasonable outcome in my opinion," Mendelson said.