Exactly, there is no guaranteed way to remove anything, HTTP status, meta-tags, headers, and robots.txt only have advisory status. They are usually followed when a resource is hit first, but once it's in the index, "keeping the result available" seems to be a top priority. I do understand the idea - it might still be a useful result for a user, but otoh if it's 410 (or continuously 404), it won't be of any use because the content that was indexed is no longer available (especially in case of 410).
Granted, these are edge cases, in most circumstances, 410 + 90 day hiding means they are hidden instantly and don't resurface. These edge cases do make me take Google's official statements on how to deal with things with a grain of salt though: bugs exist, and unless you happen to know somebody at Google there's no way to report them.
Granted, these are edge cases, in most circumstances, 410 + 90 day hiding means they are hidden instantly and don't resurface. These edge cases do make me take Google's official statements on how to deal with things with a grain of salt though: bugs exist, and unless you happen to know somebody at Google there's no way to report them.