I've seen parents let their child play with their cell phone.  Now, they think they're being smart because they lock it and they figure the kid just wants to look at the pretty colors for a minute before they're bored with it.  But time and time again, that kid figures out how to unlock the phone.  Maybe they accidentally call China...or maybe they BUY A CAR on your eBay app.  Maybe you should watch your kids a little closer when they're messing with your iPhone.