https://classes.berkeley.edu/content/2019-fall-ugba-102b-001-lec-001 says that UGBA 102B (the course in question) has a listed capacity of 120 seats, all 120 of which are reserved for business majors with 5 or more terms in attendance (which is basically all business majors, since one does not get admitted to the business major until one’s 5th semester). Current enrollment is 137 with 9 on the wait list.
The schedule also shows that, for previous terms, the spring semester typically has plenty of space in UGBA 102B, but fall is typically more full. A student who is about to graduate presumably had at least three previous semesters to include that course in his/her schedule. Also, going into one’s last semester, s/he should have chosen critical courses during phase 1 enrollment (where all students get to sign up for partial schedules before anyone gets to complete his/her schedule in phase 2).
The student trying to get into GLOBAL 173 “for a breadth requirement” should be able to find other courses fulfilling whichever breadth requirement s/he needs (GLOBAL 173 can be used for any one of three breadth categories – there are 45, 11, and 2 courses with open seats in the those categories).
Seems like this is more of a story about poor schedule planning (over many semesters) on the part of the students. In general, it is best to get required (and required-as-prerequisite) courses done as early as possible, both to avoid this type of situation and to gain more freedom to choose electives as one approaches graduation.