What is "iCloud Lock"? Seems to have something to do with having a magic number to enter on your iPhone 5 (maybe other models?) to activate or re-activate it. Is it a safety feature? An anti-theft device? I've seen some used iPhone 5 phones on sale for low prices, that the seller says they are "iCloud locked". Can an iPhone hacker get around this condition or remove it? Are these phones stolen? Inquiring minds want to know!