Minecraft Username: Iticip Brief Description: If you send a mail to a vanished player, you can tell they are online Instructions: Player A vanishes Player B /mail send player A hi How many times did you recreate this bug?: Several Result: The players name will appear corresponding to their in-game rank, rather than &c. Expected Result: The mail to be sent as if the player was offline Evidence: http://imgur.com/ihSd6Xa
I have brought this up with administration. This is intended and cannot be changed, as the way nicknames work with the mail system. You cannot see nicknames when the players are offline either. Therefore, there really is not a good way around this. Thanks for the report though!