In some municipalities where the college is as big as the town, they intentionally schedule their city elections for when school is out of session. Why have transients decide who runs the city?
Durham is larger than Duke which is a relatively small private school - not like the huge state schools. When I was there there was a big flap about students registering to vote in Durham. I can't remember the outcome but I believe the students were eventually allowed to vote. That was 20 years ago so things may have changed since then.