During the massive WWDC keynote today the folks at Apple walked the audience of developers through several new features of iOS 7, the operating system for iPhone, iPad, and iPod touch devices. Toward the end of the keynote one really interesting and useful feature got a mention but barely any talk time: Activation Lock. There were no demos or anything, but Activation Lock might be one of the most important updates to iOS in a long time.

Activation Lock builds on the security and theft recovery already available to iOS devices in the form of Find My iPhone. This feature turned on, iPhone, iPad, iPod touch, and Mac owners can locate a missing device using another compatible Apple product. The service shows where your missing device is on a map, will play a sound to help you locate it if it’s lost in your house, and will even remotely lock your device or wipe it to protect your data. All of that is awesome, but what if your iOS device is not just misplaced, but stolen? If the thief is at all smart (and hey, some aren’t…) they won’t give you a chance to find your iPhone or iPad. Instead of leaving Find My iPhone on, the thief might turn it off and/or factory reset/wipe the device themselves. If the goal is to resell the device and not steal your personal information, this method is handy.

Well, until now. With Activation Lock the iOS device will continue to display the Lock screen “please call me to return my iPhone” message even after the phone is wiped by the thief. No one will be able to re-activate or get into the device without the original owner’s Apple ID and password. Don’t have that? Enjoy your brick of a phone.

This feature is only available for devices compatible with iOS 7. That means the iPhone 4, iPhone 4S, iPhone 5, iPad 2, iPad 3, iPad 4, the iPad Mini, and the iPod Touch fifth generation and up are all compatible. Everyone else will need to keep a better eye on their stuff.

There are a few flaws in this system, of course. Find My iPhone only works when the device is connected to Wi-Fi or mobile broadband. There aren’t many deep details available on Activation Lock right now, so it’s hard to determine under what circumstances it will work – is it on automatically when iOS 7 is activated? If Find My iPhone can’t connect to the device will Activation Lock work? What if you want to sell the device yourself later on? As iOS 7 gets closer to release we hope to get the answers.

Apple is touting this new security feature as a theft deterrent, but how long will it take for iPhone and iPad thieves to catch on? And will they continue to steal devices and just sell them for parts – it’s not as lucrative, but better than nothing. I wonder how many will end up calling the owner in frustration and giving it back?