Gateway courses are high-enrollment, low completion introductory courses foundational to a major. Because these courses have a disproportionately negative impact on the retention and persistence of Latinx students to their desired STEM major, we refer to these understudied, high-stakes courses as gatekeeping courses. Framing our exploratory study with an ethnographic lens to focus on social practices that structure and organize participation and learning in the context of precalculus gateway workshops for STEM majors at a Hispanic-serving institution, we provide findings on the gatekeeping features of two central activities in the workshop: worksheets and attendance-taking. Specifically, we show how the design of worksheets, and the use of mandatory attendance can undermine meaningful learning and stymie student engagement. Our in-depth and contextualized findings into the challenges that Latinx students face in gateway courses point to the implication that gatekeeping features are reflective of passive learning instead of active learning and that significant changes must be made to improve these courses to support retention and persistence of Latinx students to their desired STEM major.