Swarthmore’s CS department is overcrowded, so it is rationing CS courses for CS majors: https://www.swarthmore.edu/computer-science/2018-19-changes-to-cs-major
But many other colleges also have overcrowded CS departments, and may handle that in different ways (not mutually exclusive):
- CS may be a limited-access major, where frosh direct admission may be much more competitive than the school overall, and/or declaration of the CS major after enrolling as undeclared requires a high college GPA and/or competitive admission process.
- CS class sizes may be very large to accommodate all of the students.