I don't doubt that the linked story is true, but I know that individually this can happen all the time inadvertently. I worked for an ISP which provided "dry loop DSL" (DSL without dialtone service on the phone line) in the mid-2000s and as a consequence of having internet service from a 3rd party over telco pairs with no phone numbers attached, the local phone companies would regularly re-use our customers' lines for new phone installations. Since they were not tagged with phone numbers in the exchange building, and had no dialtone, the phone company techs had no way to tell the lines were in use.