Not really. It might have been opened to make it look like there had been less negligence i.e. the abductor had been forced to make an unorthodox entry in order to carry out the deed rather than use the doors (which were left unlocked)
So we would be assuming here that Kate returned to apartment at 10pm to find Madeleine missing, but with the window and shutter properly secured ?
Fearing that that they would be deemed negligent for leaving the patio door unlocked she opens the window and raises the shutter from the inside in order to lessen their culpability. The abductor having determindly made his own way into the apartment by breaking in through the window , the fact that they left the patio door open, thereby, being nothing to do with subsequent events ?
OK, that's a rational explanation
exceptAlmost as soon as she down at the table that night,
before Madeleine went missing, Kate had spoken about her doubts regarding leaving the patio door unlocked. She pondered with her friend Fiona whether it would be better to leave the door unlocked so that if Madeleine woke up
again she would be able to come and find them
So then, in accordance with your theory, on returning to the apartment at 10pm, and finding Madeline missing ( but the window and shutter secure ) would she not immediately assume that the very thing she had predicted
might happen, less than two hours before, actually
had happened ( that Madeleine had left the apaertment to look for them ) ?
In those circumstances she would expect Madeleine to be found quite quickly
Why stage an abduction that would be disproven when her daughter was found ?
How, for instance, could she have explained the open window/shutter in the event of Madeleine being found at the main reception, where some kindly people had taken her after finding her distressed in the street ... that is what probably
would have happened, afterall,