FOSS gamedev and creative worlds

It would be nice, if you could see, that a player is away from keyboard (afk)!

I think it would be good if the shown playername changes to e.g. celeron55 (AFK),
when a player is afk (into the escape menu)!

What do you think about it?
Is that easy to do or not?
You have to do it in the engine, right?

You could make an AFK mod to do this, can change the player's tag color.

(There's an AFK mod on redcrab, but it doesn't change the tag color)

Yeah. I think I'll try it!
But I don't know how to change the color of a player!

Someone also could be afk while looking in an inventory.
I think it would be better to add a ping sound when someone talks to you and the mouse is not used to change the view.