I think I was but I can't remember, TBH.
I don't smack my children. It's unnecessary.
For very little children doing dangerous things I would not trust the memory of a smack to prevent them from doing it again anyway, so I would also take steps to prevent them e.g. strapping in a buggy/using reins when by any road, blocking access to electrical sockets. You'd do this anyway so the smack becomes redundant and they may not even understand. I would prefer to handle safety situations by blocking access as much as possible and talking to them about the dangers over time so that as they get older they develop a full understanding.
I believe that physical violence only seems necessary if you take the view that you must dominate a child in order to control their behaviour. The logical conclusion of this is pain and/or force, because it's the only tool that you're guaranteed to come out better on due to your physical size over your children. However, long term this is a poor strategy, because children do actually grow up and become as big as you, and likely stronger. Proponents of dominance based discipline claim that this is irrelevant because by teaching respect (by which they mean subordination) when the child is young it will remain when the child grows older. Usually they are big believers that when this does not happen, it is because a child was not taught sufficiently to be subordinate. FWIW, it's possible to believe in dominance based parenting and never smack a child but to use other techniques to intimidate them instead. If you have a child who is naturally submissive or wants to please and finds this kind of instruction clear then it might work very well. The problem comes when you have a child who is more contrary and fights against it, that's when physical discipline tends to be seen as needed.
If you instead see children as small people who are learning about and trying to figure out the world you will find you don't need smacking at all and you very rarely need to punish in any form. In fact children are incredibly willing and capable of learning in other ways. I find punishment to be a really inefficient way to teach something, because it usually invokes too many other emotions - anger, injustice, betrayal, distrust, not being listened to, not being cared about, fear, humiliation (the last two if the punishment is severe) - to actually allow what you're trying to teach them to get through. Occasionally it can be a useful tool as a temporary motivation for transient issues, and sometimes it's helpful as a shortcut especially if they are pushing boundaries on purpose, but IME you usually have to pay back this effort saved later, especially if you've used it in anger and/or not taken the time to understand a situation.
I mean, can you EVER remember a time as a child/teenager when you were punished and you immediately thought "Yep, this is totally fair" - that might come later when you're calmer and have perspective but usually the initial reaction is rage and/or humiliation and how it's soooooooooo unfair and nobody understands.