DM was looking after DC (8&6)this morning. I turned up to collect them earlier than expected and she had gone out to walk the dog, leaving them to watch TV. It’s a 20 minute walk and she can’t see her house for 90% of the walk. She lives in the countryside, has no direct neighbours - neighbours are all all a field away. I said I didn’t think this was OK (DH and I never leave DC) and she defensively told me that I was over reacting and ‘thousands of 8 year olds walk home from school and let themselves in every day’. AIBU?