I'm sure they'll only show you posts that you can see - either because they're public or because you are in one of the circles to which the post was shared. But

I'm sure they'll only show you posts that you can see - either because they're public or because you are in one of the circles to which the post was shared. But not showing a public post, even if you're not following that person? That wouldn't be a breach of privacy for sure, and it could even be useful (if maybe distracting from the subject of the email, sometimes).