According to wikipedia "secrecy of correspondence" "Paper letters have, in most jurisdictions, remained outside the legal scope of law enforcement surveillance, even in cases of "reasonable searches and seizures". "
Why is communication with letters treated differently than communication by other means?
In most jurisdictions, law enforcement requires a warrant to intercept/open/read the contents of physical or electronic correspondence.
Similarly, in most jurisdictions, a warrant is not required to read the metadata: who is communicating with whom, how and when but not what. That is they can read what’s written on the outside of the envelope or the routing information of the email/SMS.
Telephony is not correspondence because it is not the intent of the parties to create a permanent record. It is usually treated as any other conversation - if it carried out in a place and manner that the participants have a reasonable expectation of privacy it’s usually illegal to record it (electronically or by writing it down). If it’s said publicly, it isn’t illegal.
