If you are planning to buy a 2nd hand iPhone with iO7 installed (buying of “hand me downs” is widespread here in the Philippines) , make sure the “Find my iPhone” setting is off. Go to Settings>iCloud>Find my iPhone>Off. You will not be able to notice this feature since when you are in the Home Screen you will be able to call and send messages and do everything normally on it. Your problem would arise when you update your phone or restore it as it will ask you for an apple id. And if you don’t know the right id you will not be able to use your device any longer. It would be good if you would still be able to contact the person who sold it to you and ask it from him or her.
This is an anti-theft feature of the iOS7 which is good since if your phone gets stolen, eventually the person who stole it won’t be able to use it for long if he upgrades or restore the phone. The downside to this is if you bought it and sell it too to someone later on without being aware of it, the other person would end up with an expensive paperweight. There’s no workaround for this currently since iOS jailbreakers do not tolerate piracy and theft.
Also make sure to log out the apple id from the store. Go to Settings>iTunes & Appstore>apple id>Log Out and also in Settings>iCloud>Delete Account.
I hope this helps!
- Apple’s Touch ID Ironically Leads to More Possibilities of Theft (maketecheasier.com)
- This iPhone is currently linked to an Apple ID (discussions.apple.com)