Similarly, species for whom the act of producing children was not entirely enjoyable might be less inclined to reproduce.
So? Who cares if it's enjoyable or not? If we are bent on surviving as a species, why should "enjoyment" play a part?
"Or perhaps it is a risk/reward assessment when considering the possible consequences of being caught breaking the laws. "
Then why were the laws made in the first place? They are laws of Man after all.
"Why assert the existence of some vague "higher authority" when a much more likely reason does not require the invention of any extraneous entities ex nhilo?"
Because observation shows that everything has a cause. This would include "everything" itself.
Why assert "nothing" when "something" is the precedence?