I'm aware that Google is a registrar, and I'm aware of Matt Cutts' historical comments (and also John Mueller's early this year) about the folly of buying an expired domain for PR.
I've been asked to advise on whether or not someone should purchase a domain which used to be top ranking site in the niche. It currently has a 'for sale' broker's message, so even Google were not a registrar it's not hard to work out that the business is closed and the domain has changed hands.
Everything I've read would indicate to me that the purchase would be a complete waste of money. It's surely an easy thing to detect and discount. But I have no direct experience. ANd i have found that Google are not always as clever as they say they are.
Has anyone tried this recently?