per: https://postalinspectors.uspis.gov/contactUs/faq.aspx https://postalinspectors.uspis.gov/contactUs/faq.aspx Letters cannot be opened without a warrant, bu

per: https://postalinspectors.uspis.gov/contactUs/faq.aspx https://postalinspectors.uspis.gov/contactUs/faq.aspx Letters cannot be opened without a warrant, but it sounds like they could be subject to scans. In general though, almost all laws (especially with respect to privacy) were written with physical privacy in mind, not virtual. The statutes around opening a letter is much more well defined those around recording unencrypted emails.