An error of judgement does not constitute abuse. A bad one, granted, but it's definitely not abuse. I have the utmost sympathy for them, as should anyone who has an empathetic bone in their body.
I would have been taken awayby social services a long time ago if that sort of thing constituted neglect.
1. When I was about 6 being a little sh*t in the supermarket and was having to be dragged along the floor screaming, my Mum said she'd leave me there. She did, and went round the corner for 10 seconds to scare me. In that time I sprinted off and was tearfully handed in to the service desk 10 minutes later having lost her. (and it certainly did scare me). She's a wonderful person, and mother, and perhaps made a poor judgement call.
Now that's not 1/2 an hour alone in a foreign country, but I'm just saying that you can't be perfect parents, and never expect to make a mistake. Sympathise with those that do, when the worst happens.