(a) Yes, the author (me) does forget to mention that. Oops. (b) Yes, it's true that there are plenty of uses cases which won't hit the problem. But for tho

(a) Yes, the author (me) does forget to mention that. Oops. (b) Yes, it's true that there are plenty of uses cases which won't hit the problem. But for those that do, the consequences are pretty severe. And the distinction between those two classes of use cases is not obvious.