Originally Posted by
chollie
Books (or blocks of paper goods).
Supposedly the density and organic nature of paper can look suspicious to inexperienced operators.
When I'm bringing a lot of books back, something I frequently do, I pack them by themselves in a separate unlocked duffel.
No one seems interested in stealing books, and if there's nothing else in the bag, there's nothing else to steal or lose if the books trigger a bag search.
The density of stacks of some kind of printed material on some kinds of paper show up as opaque on some scanners and thus trigger further scrutiny to try to make sure it is not something prohibited or masking something prohibited.