Suzam Pal: "How does it really matter if the course is non-profit or not? Why should that stop us from calling a mistake as a mistake, a bug as a bug, an ugly solution as an ugly solution? I've participated in a few small and medium-sized open source projects where we give away the product of our hard work for free, and users benefit from it without paying anything. If there is a bug in my work, or if a user suffers due to my work, I take responsibility for it and I fix it. If a student submitted an answer without violating Udacity's specifications, and it was graded incorrectly, then it is clearly either a bug or a mistake in the specification, and in a free society, people have the right to complain about it."