Tangentially related, but the old Official Secrets act (1920) made this exception for Journalism: 5 (5): "Nothing in this section shall apply to postal packets

Tangentially related, but the old Official Secrets act (1920) made this exception for Journalism: 5 (5): "Nothing in this section shall apply to postal packets -addressed to any office where any newspaper or periodical is published, being postal packets in reply to advertisements appearing in such newspaper or periodical." (the rest of the section mandates recording the origin of post or telegrams delivered or forwarded by any business) I've always wondered what caused that exception to be made, but I've not found any historical evidence about it.