Why do long-vacated buildings still have live electrical service? Is it a lack of POCO personnel, or they don't want to go to the expense?
Or is more specifically that the previous owner/tenant never notified the POCO that they were vacating the building?
I would think the POCO would have an interest in disconnecting vacant buildings, especially large ones. Any idle step-down transformers in the building will present a continuous load that the POCO isn't getting paid for.