Hey there,
It would be nice to add check, if non-vanished player can see vanished players.
Often players check, if staff is online by using /pay nick 1

Just little check, if sender.canSee(target) would be nice / Mb. extra permission for sending money to vanished players would be great as well. Example usage for that could be found there https://www.codota.com/code/java/methods/org.bukkit.entity.Player/canSee

And implementation would go somewhere there.

Thanks much!