I recently heard from the parents of yet another high school senior who turned down a huge scholarship from a good college to attend her “dream school,” which of course has lousy financial aid. Now her parents are scrambling, trying to figure out how to pay for it .

This madness must end.

Asking teenagers to pay the whole cost of a four-year college degree probably isn’t realistic or smart. Kids may be cut off from financial aid, since need-based help is largely based on the parents’ resources. The debt they accumulate may be crippling, and students who try to pay for school entirely on their own are more likely to drop out.

But the open bar approach isn’t wise, either. Setting limits and requiring a kid to pay at least part of the cost can actually lead to better grades while protecting parents’ finances.

In my latest for the Associated Press, why parents should set clear boundaries about how much they’ll pay for college.