Sources: Puck In Flight [John Butler], The Washington Post
quote: The article seems to be talking about Precheck but discusses breaking the "code" on a passengers boarding pass, however, anything you do with your boarding pass (say reprint with different numbers) will not change your identity or create you a file under TSA Pre-check. When you go to do Pre-check what matters is your identity as that with your photo ID will be verified against the Pre-Check database.
quote: Its not talking about precheck. Its saying that if you change the one number you can avoid the normal "intrusive" search. Because the bar code scanners are presumed to be not connected to any network for real time updates.