No Support I feel this could be spammed, and then used against innocent players. Also, this is kind of what /gmsg is for, and /staff.
Sorry, but imo that might be a bit hard to do. To gmsg, don't you need them on your friends list? I was only able to get 1 moderator on my friends list, because the rest didn't accept. Also, I wouldn't always be able to use /staff, because most of the time it says someone is on, when they really aren't.
You don't need staff members on your friends list to be able to /gmsg them, it was coded in to where you're able to /gmsg anyone in /staff without them in your friends list.
Support. There should be a way to ignore this though. (P.S. Love how I am the example in all your suggestions <3)