Large strategy sets: college financial aid, and automatic weapons

One of the big lessons of market design is that participants have big strategy sets, so that many kinds of rules can be bent without being broken. That is, there are lots of unanticipated behaviors that may be undesirable, but it's hard to write rules that cover all of them. (It's not only contracts that are incomplete...)

Two examples in the recent news:

First, from ProPublica Illinois:
Parents Are Giving Up Custody of Their Kids to Get Need-Based College Financial Aid
First, parents turn over guardianship of their teenagers to a friend or relative. Then the student declares financial independence to qualify for tuition aid and scholarships.
by Jodi S. Cohen and Melissa Sanchez July 29

and
U.S. Department of Education Wants to Stop “Student Aid Fraud Scheme” Where Parents Give Up Custody Through Dubious Guardianships
One day after our reporting, the department’s inspector general said it wants to close financial aid loopholes.
by Jodi S. Cohen, Duaa Eldeib and Melissa Sanchez July 30
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Second (with pictures), pointed out to me by Jacob Leshno:

When Lawmakers Try to Ban Assault Weapons, Gunmakers Adapt
By Jeremy White