Terrific example. I agree with Thorsten, though, that another low-key conversation with the business is in order. There must be some perceived benefit for the business unit in doing it this way, and if you can identify this and show them a better way (i.e. one that does not screw up downstream users) of achieving it, that would be preferable.
Of course, if they are deliberately ignoring IT and, especially, DM, the the riot act may be in order.