Your argument is that someone should have tried to predict what random numbers people who didn’t read the spec would choose, and reserve those? That seems…quixotic. Would you reserve other numbers in this scheme, like all possible birthdays, just in case?

I would argue that if anyone had considered the possibility of people randomly choosing 1/8 addresses, the error was in reserving 1/8 in the first place. This only happened because there were no consequences to making up addresses.

BTW, 10/8 is private, and pretty easy to type.