A TSA plan to track wait-times in airport security lines is rubbing some people the wrong way. It involves using a signal from passengers smartphones to see how long it takes them to get through the line.

The plan is still in the early testing stages. It calls for using a small receiver that reads part of the serial number some phones transmit every few seconds. The device would be installed at the front of the checkpoint line and would track you until you reached the end. That information could then be posted online or in the airport to help passengers and TSA workers plan ahead.

“If it helps them be more efficient and get us through the line quicker, I don’t have an issue with it,” says Cory Cannon.

But Paul Veilleux thinks otherwise.

“I think this is just another watchdog, infringement of our freedom. I don’t like somebody being able to specifically track me and my serial number on my phone. That’s a little scary.”

But according to a report by USA Today, the partial serial number is deleted once passengers pass through the line. Passengers could also “opt out” of the program by setting their smartphones so they don’t broadcast the serial number.

John Stanley with the A.C.L.U. says,” by providing notice, the government is doing the right thing to protect privacy. But we want to make sure this technology doesn’t expand in ways that mean it will be used to identify and track people.”