So everyone should be paranoid about everyone else and hold unto their child until he or she is 13?
No. Unfortunately, sometimes things happen despite our best efforts to prevent them.
In addition, at some point you have to let your kids grow up and be independent. What that time is depends on the age and maturity of the child and what the activity in question is.
But, on the other hand, you should not be taking unnecessary risks — and leaving your kids with strangers (even if they look frum) is a definite risk.
The Wolf