BRATISLAVA, SLOVAKIA. Seventeen thousand residents' phone numbers spent more than a year on a publicly accessible municipal webpage before anyone at city hall noticed. The city attributes the incident to a mistake by one employee. The exposure cost nothing to run and nothing to stop; the first item the city has actually paid for is the apology, and apologies come from stock — pre-worded, pre-approved, awaiting a single blank: the name.

The mechanism was not a lapse in security but a category. A page that has been published is classified as finished, and finished pages are not re-read, because re-reading is labor and labor is a cost. The city notes, correctly, that open data is cheaper than guarded data, and that inspecting every published page daily would require staff it has chosen not to fund. From inside the ledger, the open file was the efficient configuration. It remained efficient for exactly as long as no one looked. The configuration was reviewed annually, at a cost of zero, and returned a finding of zero, because finding requires reading.

"The numbers were not exposed until somebody read them," said Miroslava Hrabovcová, the city's Deputy Director for Published Information. "Before discovery they were simply online, which is free. We date incidents from the moment of discovery. It keeps the statistics very tidy, and tidy statistics have never once leaked."

During the year in question, the directory did find its audience: the local harvesting trades — call-center outfits, each headed by a CEO, the dominant primate of its troop — for whom an open municipal page is a prospect list at procurement cost zero. Pavol Dinda, a shop steward for municipal technical staff, defended the named employee: "One person made a mistake. The mistake had a year of co-authors who never once opened the page. Their names will not appear in the report, because absence cannot be made to sign anything."

The invoice, itemized: to 17,000 numbered locals, one year of public reachability, non-refundable; to the harvesting trades, 17,000 prospects, free of charge, no receipt issued; to the city, one apology, drawn from the standing reserve, marginal cost zero; to one employee, the liability of more than twelve months, invoiced in career, due on receipt. The year itself is filed under a familiar heading: human error, unit price, one person.

The city's books record no loss, because the loss was booked in seventeen thousand columns the city does not keep. The ledger, as usual, balances. The question is: whose side of it.