Are rules only valid when they consider every edge case? That disqualifies almost every law, among other things.
With a little bit of moderator judgment a rule like that can be enforced. It's ridiculous to say that these bans somehow can't be done, that moderators will look at a proof that their system is imperfect and come undone.
Honestly, I think rules should cover ever edge case that you can brainstorm within 10 minutes of thought.
If some unaffiliated party can come up with the edge case easily, your rule should have a guideline about it--even if said guideline is only internal documentation.
To be fair, were I running this moderation system, I would simply say anything unclear would be dealt with on a case by case basis, and those decisions would set precedent like in the actual legal system.
With a little bit of moderator judgment a rule like that can be enforced. It's ridiculous to say that these bans somehow can't be done, that moderators will look at a proof that their system is imperfect and come undone.
It won't be perfect, but it's eminently doable.