Business
NO “expectation of privacy” in your Gmail

Privacy and confidentiality are difficult to maintain in our technical world. Legal consequences of failing to maintain something private and confidential can be devastating. Not merely the embarrassing things, but hints about technical developments patents or copyrights or confidential pricing to a customer who agrees to buy a large quantity. Of course there are also other legal implications such as a unguarded email between key managers deciding they simply didn't like a particular employee and were trying to find a way to terminate the employee for cause, which would deny them bonuses, vacation pay, and unemployment benefits.

The managers exchange the email through Google's Gmail. This is outside of the company internal email system. Aren’t they clever! Were you aware that Google's terms of service state that Google has access to all of your content and is permitted by its terms of service to use that content in various ways. No, they're not going to steal the latest copyright book that you have written, but it is not a purely private or confidential account. We have seen court cases in which the opposing party has hired investigators (or prosecutors have their investigators) to search your trash to attempt to find damning evidence.

So, if you have NO "expectation of privacy" in your Gmail, no matter how someone finds your secrets, are they admissible? Without an expectation of privacy, yes. This has already happened in at least one other state, and likely will elsewhere.  So what to do? Most ISPs provide email accounts for which you have not waived your privacy and confidentiality. You are paying for these accounts - so use them! If you absolutely must have Defense Department level of security, look for other services, but if it is simple personal/business mail with rarely a sensitive issue, try your ISP, but avoid Gmail.