H3X
It should check the admin's name first before checking the IP, because if another family member joins in while you are still an admin, it would override with their name.
Second eyes are better, I can't spot any.
The thing is, Rainbow Tag command isn't on GitHub.
I was going to post this... Very good idea, because people don't want to be bother'd like when they are building and stuff...
@robingall2910, I'm having that issue with my terminal (Mac OS) as well... 
Just tested with my telnet client (TelnetKek) as I only have it on my school computer.... 
@Commodore64x, then make an issue about it and a PR as all changes should be updated on GitHub
This would be useful for admins to see if the players is disguised. Useful if someone is trolling.
@JeromSar, it does stay invisible until you have the barrier in your hand, it will reveal it.
You can do that in Command Listener Event.