Can someone explain to me how that reconstruction could have demonstrated / proven their innocence in practical terms? And innocence concerning what crime?
Here are the points that it was supposed to cover:
E - About the Interest of the Reconstitution
Taking into account that there were certain points in the arguidos' and witnesses' statements that revealed, apparently at least, contradiction or that lacked physical confirmation, it was decided to carry out the "reconstitution of the fact", a diligence that is consecrated in article 150 of the Penal Process Code in the sense of duly clarifying, on the very location of the facts , the following very important details, among others:
1 - The physical, real and effective proximity between Jane Tanner, Gerald McCann and Jeremy Wilkins, at the moment when the first person walked by them, and which coincided with the sighting of the supposed suspect, carrying a child. It results, in our perspective, strange that neither Gerald McCann nor Jeremy Wilkins saw her, or the alleged abductor, despite the exiguity of the space and the peacefulness of the area;
2 - The situation concerning the window to the bedroom where Madeleine slept, together with the twins, which was open, according to Kate. It seemed then necessary to clarify if there was a draught, since movement of the curtains and pressure under the bedroom door are mentioned, which, eventually, could be verified through the reconstitution;
3 - The establishment of a timeline and of a line of effective checking on the minors that were left alone in the apartments, given that, if it is believed that such checking was as tight as the witnesses and the arguidos describe it, it would be, at least, very difficult to reunite conditions for the introduction of an abductor in the residence and the posterior exit of said abductor, with the child, namely through a window with scarce space. It is added that the supposed abductor could only pass, through that window, holding the minor in a different position (vertical) from the one that witness JANE TANNER saw (horizontal);
4 - What happened during the time lapse between approximately 6.45/7 p.m. - the time at which MADELEINE was seen for the last time, in her apartment, by a different person (David Payne) from her parents or siblings - and the time at which the disappearance is reported by Kate Healy - at around 10 p.m.;
5 - The obvious and well-known advantages of immediate appreciation of evidence, or in other words, the fulfilment of the principle of contiguity of evidence in order to form a conviction, as firm as possible, about what was seen by Jane Tanner and the other interposers, and, eventually, to dismiss once and for all any doubts that may subsist concerning the innocence of the missing [child's] parents.
http://www.mccannpjfiles.co.uk/PJ/LEGAL_SUMMARY.htm