If this rule is unwritten - sure there's going to be someone who will violate it some day soon.
You can't actually create a rule for this. Rules have to be enforced by an individual or an organization.
And who's gonna do that in the crypto world ? Yup it's decentralized. \
So, basically no you can't do anything about it. Theoretically, someone CAN actually create a new coin and call it the same name of an old coin but what would be the use of that ?
It won't get listed on anything. No exchanges, nothing. Not even Coinmarketcap. So, it's not gonna work whatsoever.
This is one of the things that don't happen because they can't.
yeah, that's why there are Bitcoin gold, Bitcoincash, Bitcoinforkids and BitcoinWhatever ?
And it contradicts your statement in a way, this is simple - you take 1 name + extra words, they're confusing hell of a lot, don't you think so?