All the more reason to keep anything of value in a small "personal item" that goes under the seat in front. With my feet on or around that bag, nobody is likely to mess with it. The rollaboard up in the bin is full of soiled laundry, books and such, and personal hygiene kit. If somebody wants to paw through that, more power to them. Ok, joking. I keep an eye on that as well.

The comment about locks is well taken. Sure the screeners want bags unlocked but there is nothing to stop a person from taking a couple of locks along and put them on after security.