I know a family with two very bright kids, but each failed a class in college.
One kid thought they were doing better than they were, and it was somewhat of a shock, the other seemed to be placed above their skill set, and tried to drop the class before it was too late, but the professor talked them out of it.
[he school newspaper did a story on it](http://www.westernfrontonline.net/news/article_40200e52-8b87-5ce3-86af-28d448c7e3b3.html?mode=jqm)
For a kid with seasonal affective disorder, combining a tough schedule with winter quarter was too much.
But while I think the parent might have felt like asking the prof why he didn’t listen to a student when they tried to advocate for themselves, it is separate from how the tuition is paid.
Both students now have their degrees, with good jobs, one finished grad school, the other is thinking about it.
If you never fail, it means you aren’t reaching high enough. We learn more from our mistakes, than our successes and all that. In any case, a bad grade isn’t the end of the world, and perhaps it will be motivation to check in more with the professor.
It’s been a while since I was a college advisor, but I think it is more typical for grades to be averaged, than replaced.