I don’t really get the “Cs morph into Ss” given that the deadline to declare A/B/C or S/NC is usually about 4 weeks into the 15 week semester.
Given our curriculum structure, wouldn’t it make more sense (i.e. not be astounding) that Cs would be rare? Outside of a concentration students only take classes they actively choose to enroll in (thus more likely to do well). Students can drop classes up until reading period (who do you think is more likely to drop, the student on his way to an A or the student on his way to a C)
But then again I’m guessing you weren’t looking for a real, actual discussion were you OP given this line (emphasis added)
Because everyone knows if there’s two things that define the rigor of a school’s courses, it’s whether or not you were forced to take it and when you are allowed to drop it.