Because the practice went on for months and months. Besides Kate had ample opportunity in her book to detail how they took Oakley to task when no leads were being followed. Interestingly she didn’t. In fact when Oakley did come up with one important conclusion, that the Smithman lead should be followed rather than Tannerman they simply ignored their professional advice.
"The first and second phases of the contract ran fairly smoothly. Oakley had put in place systems to gather, collate, prioritize and follow up the information coming in as a result of the appeals Gerry and I made around the first anniversary of Madeleine's abduction. There is little doubt that at that stage progress was being made.
During the third phase, however, we began to have concerns, Feedback appeared to be less forthcoming and contact with certain members of the Oakley team dropped off. At first we couldn't be sure whether this was a manifestation of the inevitble waning motivation I've mentioned or a more troubling problem. Rumours about Halligen prompted us to make enquiries before we decided whether or not we should extend our contract with Oakley. To cut a long story short we decided not to. The termination of the contract in September 2008 , was quite acrimonious, and unfortunately, that was not the end of it" - Kate from her book.