It's obvious to me that one person's opinion of what is logical and plausible may not match the opinion of another person. In my opinion opening the curtains, window and shutters would have been too risky, in yours it makes sense. Therefore our opinions about which theory explaining Madeleine's disappearance is logical and plausible are likely to differ.
What is clear to me is that the open window and shutters cannot, without corroborating evidence, be used as evidence of an abduction.
Opening the window was too risky but
1) entering an apartment unlawfully isn't?
2) stealing children or possessions from it isn't?
3) breaking into an old woman's house and spending hours there torturing and raping her isn't?
4) masturbating in front of children while their parents are in the near vicinity isn't?
or if you prefer
1) carrying the body of a dead child through town isn't?
2) Perpetuating a massive fraud and cover up isn't?
3) involving one or more of your friends and family in said massive fraud and cover up isn't?
Yes, what is considered "too risky" is a matter of opinion, and I think opening a window is the least of it.