As far as the insurer is concerned they get full premium for each enrollee the subsidy goes to the insurance company remember. What might hurt them is that the benefits for some of the lowest earning enrollees is that their benefits are so much better (lower deductibles, co-insurance and co-pays). Who pays for that?
It used to be that students could not get Medicaid, I guess Obama put that expense on the people as well. But if the student takes Medicaid and runs up a bill can they go after future earnings?
Only Medicaid expenses accrued after age 55 according to current Medicaid Estate Recovery law.