Hailey Schnorr has spent years peering into the bedrooms, kitchens, and dorm rooms of students via Webcam. In her job proctoring online tests for universities, she has learned to focus mainly on students' eyes. "What we look for is eye movement," says Ms. Schnorr. "When the eyes start veering off to the side, that's clearly a red flag." Ms. Schnorr works for ProctorU, a company hired by universities to police the integrity of their online courses. ProctorU is part of a cottage industry of online proctoring providers that has grown in recent years as colleges and univ...