What are the possible consequences if the wheel nuts are not re-tightened following a tyre change?

Your answer is correct. If the wheel nuts are not properly re-tightened after changing a tyre, the most serious risks are that the wheel can become damaged or even completely detach from the vehicle while driving. This happens because the wheel is not securely fastened to the hub. However, the tyre itself does not detach from the hub separately; it is the entire wheel assembly that is at risk. Always make sure to tighten the wheel nuts to the correct torque to ensure safety and avoid accidents.