A friend's parents had a similar system I thought made a lot of sense. While you were in post-secondary schooling no rent. They collected rent if you were just working or laying about, but that money was available for tuition whenever you want it.
Similarly, when I did post-secondary, my parents paid for all of my books but made me pay for my own tuition. When I graduated, they wrote me a cheque for the amount of all my tuition combined.
Wow! That sounds like my experience, except minus the part about the check. I feel like my parents did as well as they could for me though, and they taught me to save money in a healthy way after college.