I think there should be a command called /islandban. What it would do is you could keep your island open, and have a certain person not be able to enter it. I really think it would be useful. Also maybe /island kick, for if you just want to kick someone off your island to warn them to not break your island rules. Or alternatively, let /trusted people enter locked islands they are trusted on.
To me it is simple: either lock your island and have no one be able to visit or unlock it. Only trust people you truely trust. No support
Well maybe you could develop your suggestion a bit more, give reasons and arguments. For now I totally understand why you get no support.
Ehh, neutral. It can prevent griefs and whatnot. But you can always report the player if they break any of the server rules.
Support When People annoy me on my island but i need to keep my shop open i want to ban that one person form the island