Car Passenger: Hey... you wanna see something really scary?
Mrs. Weinstein: Birdie with the yellow bill hopped upon my window sill, cocked his shining eye and said 'ain't you shamed you sleepy head?'.
Mr. Bloom: I found out, a long, long time ago, that I wanted to be my own true age and try and keep a young mind.
Mrs. Weinstein: Remember this one, Mrs. Dempsey? Not last night but the night before, 24 robbers came knocking at my door, as I ran out, they ran in and this is what they said to me.
Mr. Bloom: The day we stop playing is the day we start getting old.
Narrator: You unlock this door with the key of imagination. Beyond it is another dimension: a dimension of sound, a dimension of sight, a dimension of mind. You're moving into a land of both shadow and substance, of things and ideas. You've just crossed over into... the Twilight Zone.
Answer: It's unlikely we'll ever fully understand. However, there were already a number of violations involving the children, prior to the stunt. It seems to boil down to the audiences at the time demanding more and more dangerous stunts and actions in their films that the film makers, and Landis, tried to accommodate. Landis also seemed less concerned about the dangers and either didn't think it would be that risky or was more concerned about finishing production on time. For whatever reason, Landis ignored warnings of the dangers. But given that he violated night time production laws involving the children, including hiding the children from welfare workers and telling them to keep everything a secret, shows he was more concerned with getting the shots and must have felt the stunt was that important.
Bishop73