Im thinking the app should have a popup with a question like:

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A person on the suggested ban list wants to join the server, will you let him join?

[Yes] [No]

Options:
[]Always ask about this person?
[]Always let this person in?
[]Never let this person in?
(This can be changed through Settings)
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Just a suggestion

Also, if a person is on the banlist, will they be banned from their own server that they make, both dedi or ingame?