What a brilliant idea! 

So you're asking, what is a Tile?

Tile will help you never lose anything again!! Keys, wallets, purses, suitcases, bikes and anything else. Just stick it on, and Tile has you covered.

If you mark a Tile outside of your Tile app’s range as missing, Tile sends out a signal that puts other Tile Apps on the search for your missing item. This all happens in the background and means that if someone else running the Tile App comes within range of your lost object, the Tile App will discretely and securely identify your item and send you a notification of its location. Not even the person whose Tile App picked up your lost item’s location will know that their phone just found your item. Your Tiles are always secure and are not viewable on anyone else’s Tile app unless you share your Tiles with designated friends and family. Once enough people are using Tile, you are able to watch your personal Tiles move on the Tile app map from anywhere.

Maybe it's a good idea to stick these on our kids!