Visible crew/equipment: When the helicopter pilot watches the kids exiting their home, a cameraman is reflected on his sunglasses. (00:35:50)
Visible crew/equipment: In the scene where Doyle is talking to the helicopter pilot at the park, you can see another pilot on the left side of Doyle's head for a split second. (01:14:50)
Visible crew/equipment: When Jeremy Renner is pushing the car, a cameraman is visible behind him to his right. (01:20:10)
Visible crew/equipment: In the scene where Don is fleeing from the farmhouse he jumps into a boat, and there is a shot about 10:24 in where you can see him in the boat and the infected in the water. However you can also see someone sat in the boat with him, appearing to be holding a camera.
Answer: Nobody ever said they could only come out at night. As their food became scarce, they'd taken to daylight hunting as well.
Captain Defenestrator