A wise way to protect the school girls. Using a pass word will certainly pay. But how long has to be seen in these days of master hackers.

Hackers can't until the child herself/himself shares it with any stranger.

Why ? Hackers can hack without anybody's sharing of the pass word.  In Bangalore schools, the child will be allowed to leave the school only after seeing a person who has been entrusted to take the child by the child's parents.

Exactly, few cases have come up where these strangers cook up stories saying their parents want such strangers to pick a child from school, if the parents give a password that only the child knows, it is difficult for a stranger to do anything. However, what to do when something goes wrong within the school premises?

There are chances of something happening in the premises. But the school principal has to answer.. At least there are chances of investigation and catching hold of the culprit.

Yes, ideally school teacher, and entire staff is responsible for the safety of school kids/children, but certainly the school magmt has failed hence now parents have to take the action.

In this particular case, it has to be ascertained first that the school management has failed.