For years, financial-industry mouthpieces warned of the dangers of strategic default, the idea that if you give homeowners relief on their mortgages, they would simply stop paying to get a better deal. This was a great theory, except for the fact that it never happened in large numbers. But we did just see a giant strategic default over the weekend – from a for-profit college.Corinthian Colleges shut down 30 campuses nationwide on Sunday, abandoning 16,000 students they promised to provide a worthwhile education.