When I was a journalism major in college, I frequently had to rent the department's equipment for my assignments.  In those instances, I learned that 1) being a journalist involves more heavy lifting than you might think, and 2) camera lens covers are very easy to lose track of.

As soon as I can afford a fancy camera of my own, I'm totally using this trick to make sure I never lose my lens cover.  Good thing I saved all those Legos from my childhood!