We never left our kids alone when we went on holiday. Once in Majorca we paid a babysitter who was from the nursery on the site we were on. She sat with the kids. I still could not settle to enjoy myself and we rushed back early only to find the girl reading and the kids fast asleep.
Apparently, there was a similar baby sitting service at this place in Portugal but the did not use it. They had left the kids with the doors and windows open each evening, but so had the others in their group. However, they have now suffered so much for what they did and I suppose they go over it in their minds all the time, so time to forgive, they made a terrrible mistake which they pay for every day, their lives are in ruin.
Lets hope Madeleine is found safe and well.