I was recently intrigued by a movie of someone breaking into a locked, zippered suitcase with only a ballpoint pen.
There are numerous ways in which baggage could be made to resist such (casual) attack. Today’s invention is one such approach.
A case would be made of tough, flexible plastic (one or both sides could be made transparent, to lessen the need for a full search before eg boarding a plane).
The top half is pushed down on top of the bottom section until the chamfered lugs (I love that engineering talk) engage with the holes in the lower part, as shown.
Then, a steel belt (like a carpenter’s tape measure) is threaded through the lugs and secured by a padlock (not shown).
This is pretty inexpensive and makes it almost impossible for anyone to access the contents quickly and without using tools to inflict serious damage.