Interesting perspective, for sure could prove handy on a nation-wide scale. The concept of googling for private keys has been around for quite a while, and here's an informative paper emphasising on how Google can Reveal Cryptographic Secrets taking the topic even further :

"Google hacking is a term to describe the search queries that find out security and privacy flaws. Finding vulnerable servers and web applications, server fingerprinting, accessing to admin and user login pages and revealing username-passwords are all possible in Google with a single click. Google can also reveal secrets of cryptography applications, i.e., clear text and hashed passwords, secret and private keys, encrypted messages, signed messages etc. In this paper, advanced search techniques in Google and the search queries that reveal cryptographic secrets are explained with examples in details."

The link for this article located at Dancho Danchev is no longer available.