Visible crew/equipment: Approximately nine minutes into this episode, as Tuvok approaches the crazed Hirogen, two stage crew members can be seen at the top left of the screen. The first is a rather plump man wearing what appear to be blue jeans, and a polo shirt, while the second is squatting down in front of the first wearing shorts and white sneakers.
Other mistake: On the planet, as the camera looks at the Harojan from behind, the zipper for his costume is visible.
Chosen answer: Before Q sent the Enterprise to the beta quadrant to officially contact the Borg, there were already indications that the Borg was beginning to reach Federation territory. There were remarks towards the end of the first season of the Next Generation that several of the furthest Federation outposts were being attacked by some unknown enemy. They suspected the Romulans, but when contact with the Romulans was re-established, they learned that it was not them. The Hansens had simply figured things out much earlier than anyone else in the Federation. They learned about the Borg nine years earlier, but Starfleet mainly took notice when their outposts started getting wiped out. It is logical to assume that there were indications of Borg scouting parties and research efforts well before that.
Garlonuss ★