A brief look at other cases reveals that basing a whole investigation on one supposed sighting is foolish. One case recently was seriously delayed because police based searches and investigation on a reported sighting supposedly of missing person. It wasn't, it wasted days, and solution was in opposite direction. In the PDL investigation it's many years spent obsessed exclusively with two sightings, both with low probability of being the missing person and probably irrelevant IMO.
Usually people make reports in good faith.
Imagine how you would feel if you witnessed something which you dismissed and failed to report; I have listened to people who will be traumatised for life because they failed to intervene or report their concerns when James Bulger was being led to his death.
On the other hand ... confusion and taking the eye of investigators off the ball ... might have been the name of the game.
It is possible decoy sightings could even have been used to deflect attention from the abductor's real route.
The PJ apparently took Jane Tanner's sighting very seriously and devoted a lot of time to working out a proposed route or destination: perhaps they were getting too close to finding that for the peace of mind of some people.
I hadn't heard of this one ... but it certainly would take resources away from the direction taken by the man seen by Jane Tanner ... and infer an alibi for a suspect.
'I SAW THE KIDNAPPER TAKE HER'Saturday July 21,2007
David Pilditch in Praia da Luz
***snip
POLICE have uncovered details of the escape route taken by missing Madeleine McCann’s abductor, it was revealed yesterday.
The sensational new development came at the end of a week of intense activity in which police sources said the 78-day-old investigation had reached “a critical stage”.
A new witness has reported seeing a man rushing past the tiny Nossa Senhora church in Praia da Luz towards the seafront at around 9.30pm on May 3, just after Madeleine was snatched from her bed at the Ocean Club resort.
The sighting – which police sources say is “significant” – backs the testimony of a friend of Madeleine’s parents, Jane Tanner, 36.
She had previously told Portuguese police that she saw a man rushing away from the complex carrying a small child wrapped in a blanket at around 9.30pm.
***snip
A police source said yesterday: “This information is being taken seriously and is potentially very significant.
“The man was seen rushing from the direction of the complex where the family were staying. He was heading down the hill towards the beach.”
The route the man took goes past a supermarket 100 yards from the McCanns’ apartment and on towards the church and beach.
It’s believed the new witness, thought to be a Portuguese local, is one of a number of people who were interviewed by detectives last week.
http://themaddiecasefiles.com/post3146.html#p3146