Me and a friend are having a debate where she claims that every and all subdomains will get crawled/indexed by google unless you specifically tell it not to, and I'm saying that if a page isn't linked to from anywhere then it shouldn't get crawled.
For example, let's say I own example.com and I make a new subdomain with a weird random name such as adayinthewoods.example.com and I throw a wordpress installation on there that I plan to use for testing purposes.
What would have to happen for google to start crawling and indexing this? Is google going to look at the whois records and see that I've added a subdomain in my DNS table and then start crawling it as a result? Is the fact I've installed wordpress on it making my installation "ping search engines"? How does that work? How do top level domains get crawled when it's a brand new domain? I assume the mechanism there is different from random subdomains.
What if I add a new page in my root folder called "noOneWillEverSeeThis.html", could that ever get crawled/indexed if it wasn't included in any sitemap and wasn't linked to from anywhere?
Would really appreciate a solid answer from someone that understands what's going on with this.