What part of this would be illegal? It's just a zigbee door sensor. The only issue I could see is the college getting upset but if anything they'd just say 'take it down'
object detection of people from images is probably what they are referring to. there are maybe some state laws that could be stretched to include that but i would say presumptively legal
Generally, in the United States, you can, in fact, just record people. Legally speaking, that is, which doesn't make it a polite or cool thing to do. Necessarily.
If you're on someone else's property, they can of course set any number of rules, and trespass those who break those rules. But even there, recording people, if against the rules, is still not a crime. The crime is trespass, if this journalist we're speaking of sticks around after being trespassed off the property.
Public university labs are generally public as they're state property (in this particular case, UW Madison is a public state University). Further, recording video or pictures of people in public places is broadly legal in the US. There are only "presumption of privacy" restrictions which apply to places such as bathrooms and private property that is not visible from a public location (ex. a sidewalk).