White students have responded by writing to each other in a cryptic code...otherwise known as cursive.
25 years ago after graduating high school a classmate described how she was paired with a black girl in a private college’s dorm as part of some goofy social experiment; when she threatened to leave (with her tuition) they relented.
I remember in college when professors assigned groups they used the rationale that in the future you wouldn’t pick your co-workers in the future. It was a good point, but I suspect few of us work in jobs with as diverse a workforce as our college classes; in fact, after the first couple of years the classes were primarily white & Asian (as others looked for less-challenging majors - we’d never meet them in the workforce in our field after graduation).