I think the purpose of opening the window/shutter was staged by the abductor to throw investigators, McCanns and even the likes of us into thinking maybe the window/shutter was used as an entry/exit point as opposed to the unlocked patio door.
But how could anyone abduct twins from creche/kids club or whatever it was referred to when numerous others were around?
MM was abducted from 5a during the hours of approx 9pm - 10pm from 5a because the abductor knew she was home alone and could gain access through the unlocked patio door. This was a totally different situation to the day care provided for twins by MW.
Holly, welcome btw, there has been a list of feasible reasons for an abductor to leave that window and shutter open.
It has been posted on here a number of times and amounted to nearly ten reasons on one occasion. All feasible.
I don't have the energy to think the reasons up again, but every one was valid.
I dont think the window was wide enough, except as a possible emergency escape route for the abductor, if trapped
The rear patio doors were in full view of the Tapas 9 and the patio illuminatedby the street lamp opposite. Amaral agreed that no-one would abduct Madeleine in sight, so close to her parents. She was only 50 metres away and in a n illuminated spot as she passed through that patio door and across the patio ... and partially down the steps.
I dont think the patio door was used because of these things and others.