I just don't think there is any rational reason to think Scotland Yard took park in that Crimewatch programme because they thought the little girl who disappeared without trace seven years ago would be sat on the sofa with the people who 'abducted' her watching it
It simply isn't logical
SY certainly did not do it for that reason. They needed to justify time and monies spent on their work so far. And the McCanns wanted to get their ideas/ message across to the viewing public. The BBC also benefited - highest ratings ever for a Crimewatch epoisode. And there is also no harm in making public appeals. The programme suited everyone.
But the McCanns - in co-operation with the other parties involved - may have chosen to mention certain things they believe could have been significant for Madeleine herself. Of all the anecdotes that KM chose to mention, she chose something that included Madeleine's direct involvement with her, regarding something sentimental. That is something that could jog the emotions and memory. Nothing fantastical about it at all.
KM could well have been doing things like this for some time.
As mentioned, this approach is a major part of the Needham campaign now. I wouldn't be surprised, if the current investigation bears no fruit, the McCanns decide to take this kind of route in a far more obvious way as part of their campaign strategy.
Why not?