2.0 GPA / C grades generally means an open major. What I am referring to is the situation where the minimums are a GPA greater than 2.0, and/or grades higher than C, and/or competitive admission, like in the given examples in the second paragraph.
Other CS examples include UIUC and UCSD, where students who do not get direct admission find it difficult to get into the CS major if they enroll as undeclared students.
A variant of this situation is where the school overadmits directly to the major, and then weeds them out with high GPA requirements. For example, Wisconsin engineering does this, with some engineering majors requiring a 3.5 technical and 3.0 overall GPA to stay in the major: https://www.engr.wisc.edu/academics/student-services/academic-advising/first-year-undergraduate-students/progression-requirements/