most kids hate having their hair brushed so her mum prolly brushed it so it looked acceptable for school and shiz and then the kid would run off doing kid things getting her hair all messy. when I have my stepdaughter over she always goes home with a couple dreads underneath her hair because she barely lets me brush it and is leggin it around the place, rolling in grass or whatever kids do which makes your hair dread faster..
my daughter will have dreads within 3 days if we dont brush it and she doesnt bathe. lol When we go camping she always comes back with dreads.