When has a cheating student's grade been so low that the best punishment was letting them keep it?

I have 2 where the best punishment was letting the keep the score they "earned" through cheating.

The first was when a student decided to cheat off the lowest-achiever in my class on the final. Scan-tron forms so the typical 1 right answer, 1 answer that appears to be right but is wrong one nothing-special answer and one that is clearly wrong (like multiply two positive numbers and one answer is negative). They both got 1 out of 50. Not a mistype. 2% on the final. I let the cheater keep his score.

The second was when a student decided to let a counselor answer their final for them, claiming it was a "practice final". How did the counselor get fooled by an obvious trick? Let's just say she was dumber than a bag of drowned rocks. And even worse than that when it came to math. I let that student keep their 0% on the final.