Southwest Airlines last week become the latest carrier to begin asking passengers for additional information under the Transportation Security Administration's Secure Flight program. The agency will use the information -- full name, gender and birth date -- to check passengers against federal watch lists, in an effort to reduce confusion and delay at the airport. A spokeswoman says passengers who fail to provide the data will notice additional inconveniences. "At the very least there would be a delay at the ticket counter," she notes. "Ultimately, they could be denied a boarding pass."