That's what it's there for :-) I've not used it myself, as I've only ever seen caches and proxies as additional domains in the list, and I'll just take those few extra pennies, thank you very much.

I do. I have a lot of scrapers, and I don't want to be responsible for what other people do on their sites in case my pub ID happens to be scraped there too. So that's my way of disavowing anywhere my code appears that I'm not in control of.

I would definitely utilise them, it's better to be safe than sorry. You don't want to compromise your account because someone has scraped your content and unwittingly your ad code!

Someone scraped my site a couple of months ago and put my G-rated content and ad code on an awful XXX site. In cases like that, I'm happy that Google knows I never gave permission for my code to be on that kind of site.