Google query

Search engines, including Google have addressed this issue some time ago which is why they follow orders from robots.txt files.
You also have the means to use 301 and 302 return codes to redirect old  links to new content, and can use 403's, 404's, etc. to block access.

Caching pages is really no different from what my browser, or perhaps your isp does. At least google eventually expires them. Try checking a site you had a few years ago from the wayback machine at http://www.archive.org/web/web.php if you want the sins of your youth to haunt you.

Wouldn't be surprised if there's been lawsuits, but who do you sue? There's been some sort of indexed search capability since at least 1986. Some cache pages some don't. Even I've written bots to search for things.

Don't forget, that the stuff that's cached by search engines, browsers, and isp's like NetZero is publically available and contains full text - including copyright notices. If it's not publically available, it's not cached.

No one can take it and claim ownership or publish without your permission. Google is less like a book, and more like a library index.

As far as cached pages go, they are publically accessible. The only fidfference between them in by browsers cache and them in googles cache is how long they stay there.

If you have information that should not be accessible to the general public, you can either put it on a page that is not named after your server's default page, and have no links to it from any other web page - which brings up the question of why do you want it on the web. Or you can put it into a password protected area.

You don't have to let google into your site. A two line robots.txt file will block it.