Google allows 3rd parties to scan your emails on demand
They just don't disclose the purpose of interaction. However if you know enough about the two people (by spying on them). It won't be so hard to guess that.
Guys at Amazon. Please start a email service and make it as a part of Amazon prime subscription. Since its a part of prime network, the costs won't be high (at least for us) and we'll get rid of the filth Google and Facebook have created.