Shielding is addressed in the paper. They did some testing covering it with aluminum sheet (from coke can not aluminum foil) which decreased detection range from 30 to 2m. That's still not a bad range compared to other similar projects attempting to detect hidden cameras using EM. But with a properly designed shield the detection is probably even worse. Within limitations section they mention, they had problems detecting some smartphone cameras due them using low power memory and in general being better shielded.