On a Nintendo DSi there's an option to completely format the system memory. It's accessed from configuration > format system memory and is so easy to select that even a 3-year-old could do it (and did!)
Is there any way I can hide this option, or make the darn thing more difficult to hit? Even the confirmation is touch screen, making it very easy to use by "accident" :-(
(Ditto for Wario Ware Touched's crazy "delete all data" option that was easier for the same 3-year-old to select than it was to restart a game - I had the whole thing unlocked as well!)