[rtkwe]

The whole point of shadowbanning is that the spammer/annoying poster doesn't know they're banned and need to create a new account to keep trying to spam/troll the board. If you tell them generally they'll just create a new account, it's especially bad for sites like HN where there's not even an email required for creating an account. As it's gotten easier to create temporary emails shadowbanning becomes increasingly more effective because it increases the amount of spam that gets blocked before the account owner notices to create a new one.