Without blacklists shipping can be expensive. There are addresses that would cost me 200,000 € if I write to them, even if the recipients log on again. Therefore the urgent request to implement such a thing. All other programs that I know have this feature.
Workaround: I import the blacklist with "active = 0 in and then delete the users, so if you want to prevent them from re-registering, they must remain in the system with" active = 0 ".
For temporary blacklists, e.g. for a newsletter, I import this with "active = 0" in a separate list. After shipping I can set "active = 1". I have not done the latter yet and I hope it works.