I have never smacked my eldest son.
My youngest son used to have extremely challenging behaviour, and I have smacked him on three separate occasions.
I smacked him because he was angry and out of control, and I did not know what else to do to try and get him to stop.
We subsequently found out that he has various allergies that profoundly affect his behaviour, his awareness of his actions, and his reasoning abilities.
The allergies were making him ill, and I smacked him because I didn't know.
That guilt is something I will have to live with for the rest of my life.
I have not smacked either of my children since then, and I hope I never will.
I deeply regret the times that I smacked my son.
Slightly off topic, but I am also very thankful that corporal punishment has been banned in schools, because I know without a shadow of a doubt that it would have been used on my son - and that is terrifying. I shudder when I think how many children with genuine behavioural difficulties must have been beaten at school in the past.
Re the article in the OP: 'Many adults were concerned about violence and unruly behaviour among teenagers in public and were worried that a ban on smacking would erode discipline further'.
There is clearly a genuine concern in society about discipline, but I think this would be solved by fostering respect for one another. Smacking does not make people behave any better IME.