During the summer following his first year at the University of Michigan Law School, David A. Rodriguez cut grass. This was unexpected. Rodriguez had signed up with a housing rights organization and, though he was happy to pitch in wherever was needed, he figured his time there would focus on, well, the law. “I don’t know if it was because there wasn’t more legal work to do, but I spent a lot of time doing more manual labor, upkeep of the various properties that they were managing for low-income …