YES to ：什么学校能让三岁的娃自己跑出去？这是最大的安全隐患。

When my son was 3, he was hit by a boy with a block and his head was bleeding. Days later,he was bitten by the same boy again! I was so mad that I went to talk to the director right away. The director put them in different classes from that day. That boy left that school very soon. I guess he was let go by the director because he made too much trouble.