[dylan604]

>imply they read your mails regularly.

No, but the point is they can. And if there is anything they feel they need to protect themselves, they can investigate. Most corp employees are just too damn busy avoiding doing their regular tasks to be bothered to snoop other employee emails. Yes, I agree that it's not like someone is just tasked with reading all email every day. The point is that they can and do when necessary. Once they start reading, they have no idea where the trail ends so they will be reading a lot.

It all comes down to the same thing stated here multiple times, don't send any messages on corp equipment that you wouldn't want to see read aloud in front of your manager/boss or worse a courtroom.