Yes Google and NSA could do such things, and I wouldn't be surprised if Russia could do this as well. But for the ordinary man this won't happen, being a personal target for the big agencies.
When you're in court having having a dispute with a customer or your boss, you can't dispute Gmail timestamps etc. That's all I'm saying.
What is your threat model? Obviously, it does not include google (and by extension, the state actors that can compel it to do things). But what does it include?