(Disclaimer: IANAL).

This is incredibly disturbing news (though alas, not surprising).

Attorney-client privilege exists for a reason. Part of that is to protect the client from lawyers acting in bad faith. But part of that is because the entire justice process breaks down if defendants can no longer communicate openly with their lawyers without fear that prosecutors may be able to get their hands on that same information.

Of course, there are other means of communication besides email (and email was never the most secure communication medium to begin with), but this still is a very dangerous step.