When my kid was 8, I would run to the grocery store that was 5 minutes away while he stayed home and watched cartoons. Sometimes I’d go pick up pizza for dinner while he stayed home. He knew house rules, gramma lived down the street, he was absolutely fine and we lived in a low key neighborhood. If he had been a different kid or we lived in a different neighborhood then I probably wouldn’t have left him. I think a lot of this is situational. When I was a kid We had a babysitting club when I was in 6th grade. The reason the rule was put in place was because some parents don’t have great judgement. I understand the rule but it makes it really hard for parents that do have decent judgement and understand their kid’s limitations.