American Airlines is testing a new technology at three airports across the country during the boarding process that aims to cut down on passengers who try to cut the line.

The technology, which is being tested at New Mexico’s Albuquerque International Sunport airport, Arizona’s Tucson international airport and Ronald Reagan Washington national airport in Crystal City, Virginia, alerts gate agents with an audible sound if a passenger tries to scan a ticket ahead of their assigned group.

“The new technology is designed to ensure customers receive the benefits of priority boarding with ease and helps improve the boarding experience by providing greater visibility into boarding progress for our team,” American Airlines said in a statement emailed to the Associated Press.

American Airlines said that a gate agent politely lets the customer know they are unable to accept the pass and asks the customer to rejoin the line when their boarding group is called. In some instances where a customer may be able to board out of order, such as when traveling with a companion of higher status, the agent has a quick way to override the alert and accept the pass, American Airlines said in the statement.

Although the technology is just in a trial phase, the airline said it had been pleased with the results so far.