well, the Danish mail service who's one of its main purposes is to read and process the mailing address correctly failed. And they most likely have _many_ more processes and safeguards than any office mailroom.
This does not include the letters that should have gone to my neighbors but was put in the wrong letter box.
While I naturally assume this is deliberate I won't rule out that this is just complete incompetence.
Now imagine you work in an office handling personal identity papers and travel documents mishandling of which is probably a sack-able offense and possibly a criminal one too. Every piece of mail entering your address has to be date registered and properly redirected. Do you think you'd just open letters without looking at the address?
In a civil service establishment handling legal documents you have to have controls on the mail, no member of staff is just going to open a piece of misaddressed mail willy-nilly, it's going to follow procedure especially in an office handling identity papers.