Flood protection/throttling

A feature I would like to see would be a throttling/flood protection feature that works like this:

If a bot, or a user comes to the site and clicks open, let's say 10 or more nodes very rapidly, the throttle script would notice this, and bring up a notice saying that "you have requested too many nodes in a very short time", maybe the script would then sleep and automatically bring up the node after a couple of seconds. Or perhaps the page would get a meta-refresh/some javascript refresh /click here to open the page to save resources that php would use while sleeping (?).

I once saw such a script in action on some CMS, can't remember which one it was. But it left the notice-page up and one had to reload the page oneself.