In Austria, we just don't have tuition fees, which also avoids these types of shenanigans :)
In Canada, they use gross income instead of net income for student grants.
So, what happens if you work in an area where the cost are high but the margin is low? You might make $100K but have $85K in costs. You still have $15K in income. Does this apply to those self employed or only wage earners (gets a paycheck)?