You can't double spend -- you would need to generate 2 conflicting tx's with the private key. Only the person that holds the money can attempt a double spend, the miners only process and include (or exclude) transactions.
Iirc that's only in theory. I don't think there has been any precedent set. But I always see people say that a warrant canary is a false sense of security.
Im always pleasantly surprised when I do a search expecting to have to click a site to get the answer, only to have ddg show me the results(a lot of time with a nice widget)
Yea, not sure what he's talking about. You can choose not to sign into Google and use the web browser to install either fdroid or Aurora as the app store. Pretty sure you need to sign into iTunes to use the apple app store and cannot install any ipa?'s.