Stefan talked about this on his guest host spot posted on Jan 31 2014 on his youtube channel. Anyone interested should read The Self Respecting Child by Alison Stallibrass, published in 1989. This book has been a staple among homeschoolers for years. It is well worth reading. Stallibrass talked about a similar situation in a park in England, where parents were barred from entering the children's play area which resulted in the incidents of accidents among the children dramatically declining.