The difference is - during the day they were away from their apartment for hours at a time, in the evening they were regularly going back and forth to check on the kids at the apartment. Stephen, I don't believe in fairies, but like you I believe that leaving a door unlocked is potentially risky, even if you feel it is safe to do so.
I confess to, personally, a slightly different take on that.
Let me put it like this.
If you were satisfied that your kids had good road awareness and the school was a reasonable distance away, you would be happy to let them walk to school unsupervised (I imagine!).
But would you leave a trail of £20 notes on the streets your children walk along to get to school?
No, of course you wouldn't.
Does that mean that you love money more than you love your kids?
No, of course it doesn't.
What it
does mean is that far fewer people in the world steal or threaten kids than money or property (thank God!)
So the McCanns were not prioritising possessions higher than their children (in my estimation)