[cryowaffle]

This is bad practice from the mailman. The lock is there so that only the owner of the box can authenticate and retrieve the mail. If he allows people to walk up and select mail from the box then he is allowing a circumvention of the authentication protocol.

[epochwolf]

It's not up to the mailman to prevent theft of mail. Most mailboxes outside of apartments and businesses don't have any security other than the threat of federal charges for mail theft.

[Cushman]

It may be worth reiterating that I (or anyone) can open my (or anyone's) mailbox with a pair of bobby pins. This "authentication protocol" may not be worth making too much hay over.

[john_fushi]

Depending on where you live the mailman can even be fired or sued.