Anyone could be at fault and sometimes, it could even be a third party and that's because kids can be easily influenced no matter how disciplined parents are.
Environmental factor a big issue many people don't consider and I strongly believe that it influences kids a lot. I am keen on the fact that parents must be their kids best friends and that way they won't miss out on anything happening in the children's life.
You are very right. Parents must develop that friendship level with their kids so they aren't influenced in the negative way so easily.