Potty training is developmental. You can't put a number on when a child is ready to be trained and forcing it creates issues if they aren't ready.
There is no such thing as "knowing better" when it comes to training.
It's not something kids simply wake up knowing because they are a certain age.
Also getting "in trouble" for anything toilet training related is against licensing regulations in most states. Shaming, humiliating or punishing a child for bathroom related incidences is unacceptable.
At 5 if the child smeared poo all over the bathroom, it was a supervision issue...not an issue about whether he "knew better or not".
This type of approach to toilet training wouldn't fly here.