Seems like TTT does not provide this kind of feedback to other players.
It only takes a couple of lines to add this. I have added an example below.
-- server-side
hook.Add( "PlayerDisconnected", "KarmaBanNotification", function( ply )
    if ply.karma_kicked then
        PrintMessage( HUD_PRINTTALK, "[SERVER] Karma banned " .. ply:Nick() )
    end
end )