Hi Dear.
Greetings to you. Hope you are fine. GOD bless you. Your explanation is very well about strictness.

Blackmail is simply a situation where by we are force to do something that we don't want to do.

It is harmful and affects the children's personality and mental health. Parents must be aware of the bad results of strictness and also blackmailing so that the children can share their problems with their parents. Parents have intensions to raise their children's personalities not abuse them but they must aware of the bad sides. Best of for the contest.. wishing you success.
Best regards @jannat12