Client side

if timer.Exists("isAFK33") then
timer.Destory("isAFK33")
end
local isAFKOnce = 0
timer.Simple(4,function()
timer.Create("isAFK33",1800,0,function()
	print("If you got kicked by accident and you are watching the console, please let bob know!")
	print("For Bob, the variable was: ".. isAFKOnce)

	net.Start("Kick_afk_network_bob")
	net.WriteInt(isAFKOnce,2)
	net.SendToServer()
	isAFKOnce = 1
end)
end)
hook.Add("KeyPress","AFK_Main",function(ply)
	timer.Stop("isAFK33")
	timer.Start("isAFK33")
	isAFKOnce = 0
end)


Server Side

util.AddNetworkString("Kick_afk_network_bob")

net.Receive("Kick_afk_network_bob", function(len,ply)
local IsDemoted = net.ReadInt(2)
if IsDemoted == 0 then
ply:changeTeam(TEAM_CITIZEN,true)
ply:PrintMessage(HUD_PRINTTALK, "You have been demoted because you were AFK for more than 30 minutes!")
end
if IsDemoted == 1 then
ply:Kick("You have been AFK for over an hour!")
end

end)