Michigan State University has a similar
tradition, but it's not exactly about what would happen if a
virgin graduated.
On our campus, we have a tower with a carillon, Beaumont tower. It's a fairly standard sort of structure, and, from the top down, is pretty squarish. At the top, on each corner, there is a spire. For whatever reason, one of these is taller than the others.
The legend is that that spire commemorates the lone virgin to ever graduate from MSU.
Unlikely, but not as far-fetched as it originally seems. When I looked the tower up to make sure I spelled "carillon" right, I found a quote from the President of MSU at the time the tower was constructed. The President, Robert S. Shaw, said that he expected the tower to become "a meeting or trysting place of the students..."
I don't know what "trysting" meant in the 20s, but I would like to think this is very clearly an imperative passed down through time by the University's president, admonishing students to get laid at the tower.