Why couldn't anything go wrong? We have free will to choose what we eat, drink, etc. Sometimes to the detriment of our bodies.
If you define the "Intelligent Designer" as God and apply this to Creation, this still won't work. As man is in a fallen state.
We are in a state of Entropy (2nd law of thermodynamics):
Psalms:102:25: Of old hast thou laid the foundation of the earth: and the heavens are the work of thy hands.
Psalms:102:26: They shall perish, but thou shalt endure: yea, all of them shall wax old like a garment; as a vesture shalt thou change them, and they
shall be changed
Or if you prefer that Alien's are the Intelligent Designers then why would they be infallible?
Either way this idea doesn't work.



