IMHO when education is subsidized by public funds (which it is here), those funds should have to be repaid if you're leaving the country within a certain number of years or before you've paid some amount in income tax.
In New Zealand, the government funds tertiary education with a zero-interest loan. If you move/work overseas, it becomes a regular loan with 4% interest.
It gives some pressure to stay in NZ, but in reality, talented engineers can get over double their salary abroad.
That would also create more incentives to simply do one's education south of the border, rather than risk being shackled by government efforts to halt one's movement.
People are eyeing the salaries they can get with that education. I can see plenty of people willing to swallow that cost in exchange for not having the government tying an anchor around their legs.