Consider the analogy where a student is rewarded with a high grade for completing homework assignments. The student discovers they can get a perfect grade by copying answers from an online solution manual, even though the intended goal of the homework is for them to learn the material. Based on this scenario, evaluate the effectiveness of 'grading for completion' as a reward mechanism. Explain why it is susceptible to being exploited and propose a specific, alternative grading method that would better align the student's reward with the true goal of learning.