Didn't test it.
lua code:
local playerList = {"Spectrus", "Eternal Oblivion", "DarkstaR"}
local whiteList = true --if true, playerList will not trigger alarm and all other players will, if false, any name on playerList will trigger alarm but other players won't.
registerEventListener(TIMER_TICK, "onTick")
function onTick()
for i = CREATURES_LOW, CREATURES_HIGH do
local c = Creature.GetFromIndex(i)
if c:isOnScreen() and c:isPlayer() then
if (not whiteList and table.find(playerList, c:Name())) or (whiteList and not table.find(playerList, c:Name())) then
alert()
return
end
end
end
end