True. But my character was still on good terms with her parents. I imagine she'd kind of like to keep that relationship intact, and returning to the Academy probably wouldn't exactly be great for that. Aside from pressuring her not to, no, they wouldn't actually be able to stop her. But they could definitely try. 

Unless of course, like Eldritch mentioned, there's something that says students are obligated to complete the three years. There's probably some sort of liability issues with just creating human/mythic hybrids and letting them loose on society. XD