If MM is found alive and well with her abductors when/how would the McCanns be notified and would they have any say over how MM and her abductor(s) are handled by the authorities?
MM will have little or no memory of her former life and if treated well by her abductor(s) would have formed a bond with them probably viewing them as her parents. The McCanns would be strangers to MM. If the media got wind of such a story it would be impossible for MM to live a 'normal' life until the intense media interest subsided.
Inevitably MM would learn about the circumstances of her disappearance ie McCanns wining and dining whilst she and her two younger siblings were left 'home alone' in the unsecured apartment night after night. Would MM want to be reunited with her parents?
Anthro has posted about the traumatic case of Zephany Nurse who was kidnapped as an infant; there are also recent American examples and the children of the disappeared in Argentina.
Whatever the circumstances of a child being stolen it is almost never an easy transition back to what should be normal life for anyone involved.
To celebrate the added difficulties which Madeleine may experience if found alive as a result of a best selling book which decreed her dead and the hateful and continuing hate campaign which followed hard on its heels is disingenuous to say the least as her very survival would prove that all of that was wrong.
I think that anyone who participated in that campaign in any sort of way should be hanging their heads in black burning shame not crowing about further harm being done to a young woman whose life was stolen from her.