I'm kind of appalled by the mention of looking through the team's emails and IMs. Is this common practice?

Maybe my experience isn't representative, but everywhere I've ever worked, we've operated under the assumption emails and private IMs are, just that, private. We know that ultimately management could look at those things, but the assumption has been that privilege is reserved for extreme situations (e.g. a lawsuit, an HR dispute, etc.).

Would love to know how it works elsewhere.