For any map, what it shows is limited by the data available. You chose to two somewhat different universities to highlight your perceived problem. In preparation for this response, I visited the websites of both Duke University and the University of North Carolina, Charlotte to view their own maps. In each case, the University's own map is significantly different from the Maps version. Duke University's campus is much less contiguous than is shown in Maps. Many of UNCC's boundaries appear to be lines drawn in the dirt.
As you know, Maps is crowd-sourced. Each feature in Maps is based on input from numerous individuals. I find it easy to see how the crowd would have difficulty defining the true boundaries of UNCC. I also find it easy to see how the crowd would be just plain wrong about many of Duke's boundaries.
This situation appears to be on the verge of change. Google Maps are based on satellite data and numerous trucks driving on actual roads around the planet. Apple appears to now be following the Google model for collection data for Maps.
