I had a lot to do with Safeguarding when this happened and it always came up at meetings:
1) There would never have been a conviction in this country if a Mum & Dad were sitting in front of a Tapas Bar while their flat/room was 100 yards away, that is not abandonment and especially when they were being looked on every 30 seconds.
100 yards, 30 seconds. A quick Google suggest average walking speed is ~109yd/minute. In order to cover the 200yds to the room and back every 30 seconds, there would have had to be a constant relay of people.
2) There were 7 adults and several children in the party so you need to arrest them all.
Rubbish - it's the parents responsibility, not their friends' (unless they were specifically entrusted to look after the children in the parents' absence.)
4) People are still doing this on holiday. Sit round a pool in the day and observe and then wonder where the children are in the evening.
This entirely depends on the age of the children. I would happily leave my very sensible 9 year old on his own for an hour or so, in a locked room, provided he had some way of contacting me (e.g. mobile phone) or I could see the entrance/exit to the room/block of flats. I certainly wouldn't leave a 3 year old alone for more than a couple of minutes - even ignoring any outside interference, it takes no time at all to stick fingers in electrical sockets, climb & fall off furniture, wrap a cable round their neck, etc.
If they're asleep, then at the very least take a baby monitor so you can hear if they wake up and are moving around etc.
