I can't see how they would enforce this but, I suppose they have to try.
Source: Neowin.netApple is seeking support from the federal government in hopes to overturn the recent decision by the courts that legalized jailbreaking. The U.S. Government Library of Congress Copyright legalized jailbreaking and unlocking of devices, allowing the user to run unauthotized applications on the device.
Jailbreaking is a term used by the iPhone hacking community to bypass Apple's restrictions on the device, allowing for the user to run programs not approved by Apple on the iPhone, iPod touch and iPad.
NBC News reports that Apple is attempting to overturn the decision made by the courts back in July, in hopes that they will get a ruling in their favour to make jailbreaking and unlocking illegal. Apple's argument is that since jailbreaking has become so wide spread, it just leads to piracy of apps.
Although Apple may have a point, not every person who jailbreaks their device does it for pirating purposes, but may do it to modify their device and allow alternate carriers or download apps not approved by Apple.Current jailbreak technologies now in widespread use utilize unauthorized modifications to the copyrighted bootloader and operating system, resulting in the infringement of the copyrights in those programs.