Disenrollment happens for a number of reasons, but if you are a "scholarship' student, you may end up with a debt to the government and it could be six figures or more depending on your school. Usually you are OK if you "quit" prior to disenrollment within the first two years as the government is generally more accepting of your leaving prior to you beginning your Junior Year.
There have been threads on here where Sophomores failed to get a waiver, were scholarship students thru ROTC, the school they choose was beyond their normal means of finance and they ended up disenrolled for medical but were still responsible for their tuition (or so it was claimed) and they had to transfer, eat a whole year of government payments (because they were never cleared for service medically but took the money anyway), and either the parents paid the school (because the government took back the money) or the student had a pretty big debt.
Just my personal feelings, but if you use an ROTC scholarship to attend a school you would not normally consider (for academic or financial reasons) just to get a degree from that school, be very careful. One never knows what may happen three years in, academically, physically, or discipline wise, if you are disenrolled or dropped a lot of times the government goes back and gets it's money from the school and absent Merit or Needs based aid the student could be on the hook for a lot of money.
Normally, things work out just fine, but you don't want to be that person for whom there are problems and you get stuck with a debt load. JMHO, maybe better to find an in-state tuition school that offered the major desired over a much higher priced, more prestigious school. That way if they had problems the amounts owed would be far less and manageable. I am not sure, and this is not FACT, but posts on this forum seem to indicate that even if you attend an expensive school on a Academic Scholarship and needs based aid then get an ROTC scholarship, it seems like the school cancels the Merit and Needs based aid and uses the ROTC money, and if there are problems it was indicated it was difficult if not impossible to get the financial aid back after the fact to cover the debt from the ROTC scholarship. Just be careful, and use good judgment as far as ROTC Scholarships go, many programs cannot or do not offer the support and guidance that a SMI or Academy do and students sometimes can go off course and lose that ROTC money. Research, Research, Research, and pick what you think meets your needs remembering nothing is guaranteed.