That’s a good idea,but google sometime crawls without the google user agent. So that’s not going to be 100 percent foolproof. You’d be better off just blocking

That’s a good idea,but google sometime crawls without the google user agent. So that’s not going to be 100 percent foolproof. You’d be better off just blocking all of the ip addresses that google crawls from. There are lists of those out there. When I used to cloak website content, and only serve up certain content to google, the only reliable way was to use ip cloaking. Because google crawls using “partners”, such as using Comcast IPs. So if you’re want to really get your site out of the index, serve up the page with a noindex tag or noindex in the server header based on google ip addresses.