My question again, addressed to those with anything to add to the discsussion.
It could only be theoretical at best.
"Jane actually DID see a man carrying a child from the direction of the apartment at 9.15 pm. So, what then happened next vis-a-vis hatching the convoluted plot, involving whooshing curtains?"
In my theory Crecheman was taking that child to the McCann's apartment as part of a prank being played on Kate, but when Jane appeared on the scene it became impossible to walk down to the side gate without blowing the prank. Someone else had to do Kate's 9:30 check so they had extra time to set up the prank.
But no one budgeted on the burglars opening the shutters and that noise waking Madeleine so the whole prank turned to custard.
At 10:00 they think the scene is set but it has all gone wrong. Kate discovers the whooshing curtains. The guys don't know if the crime scene left by the burglars was part of the prank or not so the crime scene is not preserved.
That is how my theory worked.
Mark Rowley sums it up nicely: "However Madeleine left the apartment, she was abducted"
The prank should not have resulted in Madeleine being lost, so they assume she was abducted.