No. IMO, someone crept up the back Patio Steps, got in and then abducted Madeleine and took her out of the front door. The open window could well have been an escape route if the abductor had been caught at it.
It's all quite simple, albeit a bit risky, but it was always going to be that.
Apologies for exhuming a post 2 days old, but I've been reading back.
Why would an abductor require 3 egress points be made available, given the additional time, trouble and effort, plus disruption and noise?
Knowing a few ex-housebreakers (council estate upbringing / questionable judgement of friends), if they could open another door or large window from the inside easily, they would, but in the main they would go out the way they came in. They had many little techniques, such as using a shovel to lever patio doors, using that same shovel to place on the stairs for a roused occupant to stumble over. They generally would be opportunistic. They would rarely enter an occupied house unless they had additional knowledge of the occupants. They would avoid houses where the comings and goings were frequent, but would have a quick go at a gaff if they saw the occupants routinely leaving doors unlocked.
Doesn't matter if you're stealing a JVC VCR, a Faberge egg or a 3 year old girl, the risks of being disturbed and methods are the same.
Was the front door a Yale type lock or mortice, or both? Was it possible to open the front door from the inside without a key?