richms: They are ok with putting it on paper and leaving it in a roadside box so clearly it is not that important.

 

It is seriously illegal to open postal mail addressed to anyone other than yourself.  That provides a decent measure of protection.

It's ssl from their mail server into Google or whoever and then access to it is secured by 2 factor. Much better than paper that can get lost easily, is harder and lossy when backed up and needs scanning to pass on.

And you seriously do not think the US intelligence agencies have access to Google?  If you encrypt it, then no-one except the recipient can read it - even if they have a court order.  Without that, anyone with access to one of the intermediate servers can read an email.  Or alter it.