First, you are threatening a child, which makes them fearful of you.
Second, it ignores your responsibility to deal with the issue at hand and passes it to someone else.
So, you can say “Walk, please” instead of “No running”. Children are programmed to question, analyze and wonder about situations.
I have spent a good deal of time on articles on the difference between Praise vs. This can sometimes present itself in an argumentative manner, but this is actually a normal part of development.
Telling a child that they can’t do something makes them prove that they can, by telling you or showing you that it is in fact possible.
Telling a kid to not do something makes them want to argue or rebel.