The stop at the Peace Bridge vaulted Shearson on a legal odyssey that delved into a secret world of watch lists and something called the Automated Targeting System, a massive computer program that border officials use to track and rank suspected terrorists. As the computer files grow in size and scope, the inaccuracies grow as well, according to Shearson, security experts and U.S. Justice Department reports. For Shearson, the errors surfaced on Jan. 8, 2006, as she was returning from one of her favorite escapes. "That's my de-stresser -- to go on a road trip," she said. "Everyone goes to...