Apple doesn't need a reason to reflash the baseband. When we upgrade our Nokia's software we normally reflash the kernel, initfs, and other stuff that probably doesn't need to be reflashed for simply updating the software.

What Apple really needs to explain is why the previous contents of the baseband are significant to the upgrade process. They also need to explain how hackers could irreparably "damage" the iPhone software. After all, if hackers were able to rewrite the baseband with a software unlock, should Apple be able to re-lock the iPhone with software?