My brother, who used to work for the Post Office, told me that new mail slots are not permitted, old ones are grandfathered in. The ostensible reason to prevent injuries to letter carriers, the actual reason is because the post office could not compete with bulk carriers.
When did this no mail slot rule take effect? I had one installed about five years ago; no one said anything to me about them being illegal.
And how does the carrier get injured from a mail slot?