So basically the authorities will have access to your e-mails anyway. It's just that they won't get them in the first 180 days. And of course this just applies to police/FBI, as NSA can get them from the day you sent them.
http://video.foxbusiness.com/v/3899047/google-ceo-recession-...
It's a non-trivial engineering task. If you want an email service which can readily delete your email, you need to find one with non-redundant, completely un-mirrored databases, fragile filesystems, and no backups. But that is not what most people are clamoring for in a service provider.
Each of them believe they are doing nothing wrong.
I wouldn't be surprised if the NSA didn't have the e-mail captured, sorted, and analyzed before it's processed on the receiving end and shows up in the user's mailbox.
How is this not the wide assumption being made right now? How is there ANY question remaining of whether or not they have such access?