While I sort of agree, it's not about a fence but getting as much info as reasonably possible before acting. Next time you change something you don't understand because of curiosity, there may be injuries or deaths.
> This is typical of the dogmatic approach to reasoning that you find in many religious texts
That's pretty much what you've done here; taken the extreme view of what I'm trying to say.
Back on the subject: the dot matrix printer was not the guy's property and it may have been streaming a hardcopy of some server's intrusion log. That would explain why it was there but nobody looked. It's there in case someone ever needed to.
(edit: it's printed door movements, not server stuff. If the doors are opened by badges, it's still movement detection, at least of the most basic, people-y, sort)