When Apple launched iOS 7, it added a security feature called Activation Lock that would prevent someone from erasing or activating a device without first entering the user’s Apple ID. It is enabled automatically when you turn on Find My iPad or iPhone. Because of this new feature, a device is rendered useless if it is resold while still activated. That’s why companies like Gazelle and NextWorth estimate your device’s value at “worthless” if you haven’t deactivated the feature.
Source:
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