I suspect you're right. You work in a place like I do, a profit bearing company, I would think you are like me and just assume, any email I send could/could not be read by the employers. I would think it's fair to assume the same thing here. If you (as a company) suspected there was a good deal of dissent. Would you read the emails you had access to? I strongly believe in a persons right to privacy, but I also know, when I write an email it work. It can be read.
Not saying that won't happen here but it could.