You know I am (also) a lawyer and have written a couple of contracts myself (the last one about some $10,000 about two weeks ago) but often I cannot wrap my head around these Google terms (they are also contracts between them and you).
In my opinion, what is not explicitly forbidden (by a contract OR by a law behind it) is allowed. They are careful enough to cover their interests so if they do not make it clear what we should not do, we can do it.