Summary

This is a more complicated design than the original (http://www.thingiverse.com/thing:641018) but works better if you have little inquisitive kids.

The original worked well for weeks, until my son figured a way to wiggle the protectors loose repeatedly. Eventually he won.

My 5-year old came up with this design that she was sure would stump her brother. 9 days later, he has yet to figure out how to dismantle this. :-)

The tab at the back links the two halves together, making it very hard to slide either protector off.