If you want to make your point Carana why use a case where it was gross stupidity rather than propoganda which left the young girls undiscovered ?
Could it be because you have no relevant example ?
How can it be determined whether two cops were incredibly naive (hadn't been sufficiently trained, hadn't been given sufficient information) or had been led to believe that the kids were dead and were therefore less attentive to potential indications that they were indeed being held somewhere?
The Dutroux case is complex. And it led to a massive overhaul of the entire Belgian police system.
That said, I doubt that the UK officers who found Shannon really believed that the tip concerning a house was anything more than a routine check, and they could easily have missed her as well.
Police officers are human, after all. Hope is no doubt high in the beginning, but that hope no doubt deflates as time goes on and newer cases have to be dealt with. That's probably natural. However, if your superiors are also giving out vibes that it's a lost cause, then how easy is it to maintain enthusiasm?