In the following scenarios:
Scenario 1 - in the daytime for an hour or two
Scenario 2 - in the evening for a couple of hours, parents 15 minutes away
Scenario 3 - in the evening for a several hours, parents 30 minutes- 1 hour away
There are no official rules on this, but I understand the parents are responsible for all children until age 16, so if something terrible happens it's the parents who are held responsible. After age 16 they can be held responsible (not sure if this is any better tbh!).