Last year, I enquired with an education provider on this matter. They explained the following:
- A foreigner can only obtain a Migraciones student visa if studying at an institution that is accredited and registered with Migraciones for this purpose (the institution in question was registered with Migraciones).
- Each semester, as part of its accreditation with Migraciones, the institution is required to report to Migraciones the status of its foreign students taking its program on a student visa.
So the university is no doubt a Migraciones-accredited provider, but we can be sure there is a regular feedback look between the two. It's part of the contract.