Add a way so other people cant fly into your island when it is locked or kick everyone off the island. Make it so people cant have homes on your island. People keep coming my island in /v and bothering me. For example when im trying to place blocks they would stand in the way. They would also kill the mobs I try to afk. They also kill my friendly mobs such as snowmen.
Support for all the suggestions listed by @Stabbi . There is already /lock and /unlock, but I think these suggestions should still be implemented because they also point out how people can circumvent the /lock command. Maybe upgrading the /lock command would be a way to implement these ideas? or adding a command like (making this up) /IslandClose or /isclose to remove all homes from the island, all people that aren't trusted, cooped, or the island owner, and stopping people from visiting via /fly. (Undone with something like /IslandOpen or /isopen) Not sure if this can be easily added though...
Being that you can't receive damage on another players island, possibly make /fly only available on unlocked islands unless you are an owner/trusted? The above would mean as soon as you leave your island, if someone has a locked island, you lose /fly (possibly dieing, but eh that's the risk they take) which prevents people randomly showing up at your island. Assuming an island is unlocked or you are trusted/etc, you could use /fly.