This is what happened to a 3 yo child at the nursery my niece attends . My sister was telling me this morning about it.
The nursery staff decided to take the children (aged between 2 and 4) one day last week to the park which is a 5 minute walk away from the nursery. They apparantly done a count of the children before they left nursery, but didn't when they left the park. It was only when they returned and one of the Mothers came early to pick up her child said " oh, where is so and so today" that the staff realised they had left him behind .
The child was still in the park when the staff went back playing quite happily, but more worryingly is there is a busy road literally 1 minute walk away .
Anyway, the mother that noticed the child was missing contacted the mother of the child, and she sent letters out to all the parents saying what had happened, and has taken her child out of playgroup (understandably).
HOw can you forget a child?? The park in question is quite small too, and not a particularly busy park.