As as an adjunct I can tell you this is actually a big problem especially at the Associates degree level online. Up to 20% of the students in a class never complete an assignment, or do one or two quizzes to stay enrolled, and do not respond to emails. I can tell they are fake or bots but somehow administraiton never can. Certain online schools and community colleges have been milking this I suspect. https://www.foxnews.com/politics/trump-admin-drops-hammer-ghost-students-claws-back-1b-from-alleged-loan-scammers
The one where I instruct that has a problem is a RA private for-profit university with a campus and online operations. Although I understand from Reddit instructor forums that this a major issue at community colleges nationwide too. The students are always AA or AS students in my case.