Originally Posted by chollie

I've read that piles of books can look suspicious somehow. Last couple times I brought back a stack of books (8-12, I like books), I checked them in a separate small bag with a couple large ziplocks full of dirty clothing. That way if the bag did get opened, there wasn't much to rifle through or steal. Isolating something that might trigger curious xray eyes (if possible) is a good idea - whether it's tent poles, books, blocks of cheese, etc.

It's difficult to do now, but I still have some pieces of luggage with metal zips which are immune to the ballpoint trick. It also helps if you use a ziplock to secure the zipper pulls to something else (gear loop, handle) on the luggage so that if the zip is compromised, it can't be resealed.