I don't believe your analogy holds. Reasonable people understand that other humans will necessarily see the exposed-in plain-sight content of a postcard in the

I don't believe your analogy holds. Reasonable people understand that other humans will necessarily see the exposed-in plain-sight content of a postcard in the process of delivering postal mail. However, reasonable people know that no humans are required in the process of delivering e-mail, and further, the average person doesn't necessarily believe that other people will read an email even if they know it is technically possible.