Where I live (and I guess it will be similar-ish elsewhere) children aren't allowed to leave school alone until year 6 (last year of primary, age 10/11). However, the secondary schools start and finish approx half an hour earlier, and there are quite a few kids who get collected by older siblings. Katie is in year 3, the same as my 7 year old daughter who wouldn't be allowed to leave with anyone but an authorised person so I'd b surprised if she was walking home alone.
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