Being an iPhone developer is like sitting on a gold mine today. If you manage to get the right apps out on the AppStore, you could end up with a mini fortune in no time. But the iPhone SDK released to developers for building apps is the source of raw material for Jailbreakers and hackers.
Apple has already tried to get Jailbreaking labeled as Illegal. And now the attempt is to restrict the support jailbreakers get from authorized iPhone developers.
Many iPhone developers are known to release their rejected apps on Cydia for jailbroken iPhones. However, doing so would now mean losing your developer status with Apple (probably). However, we doubt if this would derail the jailbreaking community. Just another wall in place by Apple.