@daringfireball Your presumption is correct. The indicator light is still software and this still means it is susceptible to compromise as all software is, in a way that a hardwired indicator cannot be. Sophisticated exploits achieve privileges beyond the kernel’s all the time.
@daringfireball The solution they picked does make it non-trivial to bypass and it is a good choice if a hardwired indicator is not available. However it is still substantially less secure than having one, and Apple knows it.