Anti-CoreGui injection help?

I'm quite stuck on an issue. I was working on a way to stop exploiters from adding in a custom guy to CoreGui, similar to how EISS works. However, I'm at a stand-still. Anyone have any scripting help on this?

--Basic Code Idea
function RemoveAdded(item,par)
if item.Parent == game:GetService(par) then
wait() -- needed to remove without errors
item:Destroy()
end

-- Child added function
game:GetService("CoreGui").ChildAdded:connecrt(function(child)
pcall(RemoveAdded(child,"CoreGui"))
end)

I know that this will not work, and I'm currently on mobile, so I can't test it out. Any help?