Yup. That's part of why I'm such a big believer of showing them a hard copy of their regs and TSA regs. When you show up and they can see you've done your homework, they tend not to challenge you on that stuff. Even the little comments cut back when they realized I was better prepared then they were. If they want you to leave it unlocked, I would absolutely resist. TSA laws state that only you may have access. "But I'd be more than happy to accompany the bag to secondary screening, it's really no trouble...."