an anonymous reader writes "Apple's recent decision to void warranties for folks that unlocked their iPhones may wind them up in legal hot water. The site Phone News points out that Apple appears to have broken a key warranty law relevant to SIM unlocks. The Magnuson-Moss Warranty Act, a law decades old, would seem to prevent Apple from voiding warranties in the way it is threatening to do with the iPhone, or so the site argues. 'The Magnuson-Moss Warranty Act states that Apple cannot void a warranty for a product with third-party enhancements or modifications to their product. The only exception to this rule is if Apple can determine that the modification or enhancement is responsible [for] damaging the product in question ... The legal [questions are]: Is the SIM Unlock process that has become mainstream doing damage to iPhone? And, also, is Apple designing future software updates to do damage to iPhone when said SIM Unlock code is present?'"