From wired, comes a simple but effective way to detect tampering of devices.
The secret is to use glittery nail polish and pictures. Glittery nail polish, when applied, dries into a random pattern. It can be applied to joints, screens, covers, etc. A picture is taken of the 'seal'.
Upon return, take another picture, and then compare the two. By quickly flicking between two pictures, it is possible to discern differences. If differences exist, equipment may have encountered tampering.