Corrected entry: When Buffy and Spike argue about the wedding and she says "You think I don't live with the shadow of Drusilla over my head. Like you won't be thinking of her when you're making sweet love to me," you can see a crew member wearing a light sweater at the right edge of the screen. (00:26:30)
Corrected entry: When The Initiative are looking through the thermal goggles, it shows the first three or four people before Spike to be 68.6 degrees. But not everyone's temperature is 68.6 - it's just an average. Running or even talking could make it a different temp.
Correction: As you say, that's the average reading, and there's not a lot of variance from that. It stands to reason that a sampling of only 3 or 4 people could all show the same temperature.
The Freshman - S4-E1
Corrected entry: At the end of the episode, when Buffy is fighting the vampires, she grabs a tennis racket, and just before she hits the vampire with it, the head of the racket flies off to the right of the screen and she continues to swing round and hit the vampire, running at her on the left of the screen, with the racket (minus the head).
Correction: That's not a mistake. All this proves is that even in the Buffyverse, tennis rackets can be poorly made.
Corrected entry: In "The I In Team", Buffy tells Maggie Walsh that's she's always wanted a pager. Buffy has already had a pager, seen in "Never Kill A Boy On The First Date". (00:12:05)
Correction: In "Never Kill A Boy On The First Date," she grabs Giles' pager out of his front jacket pocket when she says "If the Apocalypse comes, beep me." Buffy hasn't had a pager of her own prior to this moment.
The Freshman - S4-E1
Corrected entry: The vampires shouldn't be able to get into Eddie's room without his permission. Or does that rule change when the person who owns the property has died?
Correction: Once the owner is dead, the rule no longer applies. Not that it entirely matters in this particular case - dorm rooms, like hotel rooms, are not deemed to be 'owned' by the occupiers, they're considered to be public spaces. As such, the vampires can enter freely.
Fear, Itself - S4-E4
Corrected entry: The little demon is standing right next to the hole in the floor where Buffy ripped up the floorboards - so wouldn't her foot have gone through the board when she stamped hard enough to squash it?
Correction: How hard do you have to stomp to kill a bug? Or a mouse? Normal body weight easily does the trick.
The Harsh Light Of Day - S4-E3
Corrected entry: When Spike and Harmony are near to the area of the Gem of Amara, Spike tells Harmony that she can't go out anywhere. Harmony is wearing a pink corset top, but when they reach the actual area of the gem, the top changes to a brighter pink halter neck. This happens in a short space of time, so she wouldn't have had time to change.
Correction: She would have had time to change. There is a whole sequence in between the two scenes with Harmony changing clothes that shows Buffy at various points during the day (she checks the answering machine several times). Several hours have probably passed between the two times we see Harmony. It could even be the next day.
Corrected entry: Towards the end when Willow is in the science lab casting her spell you can see the wires that are used to levitate the vials. They are especially noticable after the vials drop and you can see them dangling there. (00:35:20)
Correction: Having watched this scene through at normal speed and in slo-mo, no wires are visible.
Corrected entry: In the scene where they look through the window into the room with thermal cameras, there is a big mistake: Thermal cameras can't see through windows.
Correction: This just isn't true. Depending on the type of glass, windows may or may not absorb or deflect IR radiation (heat). Industrial and military IR scopes/goggles can also be tuned to enough sensitivity to nonetheless provide an image. Moreover, advanced scopes can combine signals from multiple sensors at differing sensitivities in order to allow a more complete image.
Corrected entry: Everyone who writes on a white board does it with the same handwriting. (00:20:30 - 00:29:20)
Corrected entry: Room 314 is supposedly in a high security sector of The Initiative which needs to be accessed by a keycard, but in "Goodbye Iowa" all the soldiers are gathered around the door of it to see Walsh's body. How did they get in there? (00:13:45)
Correction: Assuming that the scientists working with Maggie aren't expecting her to be lying dead in the room then the first person to enter the room would most likely stop at the doorway in shock. After that all it takes is for people to stop at the door wanting to see whats made this person stand there & it would snowball from there.
The Harsh Light Of Day - S4-E3
Corrected entry: When Spike grabs the ring of Amara from Harmony he's still wearing the huge necklace he had thought was the gem, when he turns around to leave the necklace has disappeared. (00:32:55)
Correction: Spike grabbs Harmony's arm to look at the ring (before taking it), he puts a cross to her head to see if it works and when putting down the cross he also takes off the necklace.
Corrected entry: Buffy and Willow's have dorm has communal bathrooms. Why then does Willow choose to do her spell in the bathroom where anyone could walk in on her?
Correction: It's late at night and she probably doesn't want to wake up Buffy. The bathroom is probably the most secluded place to do it.
The Freshman - S4-E1
Corrected entry: Several times throughout the show, we have seen that Angel - a vampire - cannot enter Buffy (and Willow's) dorm room on the college campus, due to the invites only rule for vampires. So how did Sunday's vampires get in to steal all of Buffy's things?
Correction: There are only two other times that we see vampires enter dorm rooms. Once was Spike (The Initiative), the other time was Angel (The Yoko Factor). Neither time is it made clear that the vampires CAN'T enter the room without an invite, but likely just wait for the invite out of habit. so it's entirely possible, since it's seen that school buildings are considered public, that vampires really don't need an invite to enter the rooms at all.
The Freshman - S4-E1
Corrected entry: On Buffy's first day of school, both her folders and the school banners use the acronym UCD, though the school is actually University of California Sunnydale. The crew used the fliers from UC Davis.
Correction: The folders have a sun between the UC and the D. The folders then read UC(sun)D for UC Sunnydale.
Corrected entry: In "The Initiative" in Season 4, Spike is given the chip implant that causes intense neurological pain if he harms a human. We see this take effect when he tries to bite Willow, but he was able to beat up the doctors at The Initiative to escape.
Correction: It's possible the chip was only activated after his escape from The Initiative.
Correction: It's Spike's head and not a crew member.