I was told to do something that was a crime by my line level manager at a tech company when I was only a few years in my career, with code that he hand wrote and wanted me to type in and commit under my name.

When I refused he called me into a 1:1 and verbally told me I would be losing my job if I didn’t and only backed off when I told him he was never getting that paper back and asked if he wanted to go HR right now at which point I would be going to legal and didn’t care if I lost my job as long as he was implicated.

Only time in my career it’s happened, but it happens.

In my own experience, the brass sets the culture and expectations that encourage department heads to break the law. Certainly there are done CEOs explicitly commanding people to do crime, but it's more common to tell people to, eg, move fast, focus on profits, and do whatever needs to get done.

It's standard policy at most major corporations even for low-level employees to not discuss anything legally sensitive over company e-mail or chat.

You vastly underestimate how much they take care of things. At the top people manage liability.