Plot hole: The ghosts cannot cross the front gate since they died on the mansion's property, however, the Viking and Native American died before the property was laid out, so they should not be limited by the later boundary lines.
Continuity mistake: Pete's arrow is sometimes straight and sometimes crooked. Since it's the manner in which he died, it should be consistent.
Continuity mistake: When Sam is in the bathroom holding up two sample paint chips, in the first shot she's holding up the yellow in her left hand and the blue in her right hand, but in the next shot they've switched and are in the opposite hands, just as Jay arrives with the coffee.
Factual error: Pete died in 1984. Yet mentions the movie 'Ghost' with Patrick Swayze which released in 1990.
Suggested correction: It is established that the ghosts have watched television, listened to the radio, smelled pizza/pepperoni, etc. It's not impossible that Pete saw Ghost on TV.
While they do watch television now, it's unlikely that Sophie watched "Ghost" and that Pete saw it alone. The reply from others was "you know we don't know what that is" and he said "oh, right the movie thing." Which was a call back to earlier when Trevor was trying to explain who Tara Reid was and the older ghosts had a hard time knowing or remembering what a movie was.
Factual error: The ghost doctor says he's been in that building for 85 years, meaning he would have died in 1936, but the stethoscope he wears was developed in the 1970's.
Dinner Party - S1-E4
Revealing mistake: Issac is reflected in the cabinet door when Sam is asking for the ghost's help.
Suggested correction: When was it established that the ghosts' reflections aren't seen?
Continuity mistake: At the foot of the stairs, Higgentoot is facing away from the group, and his hands are by his sides. As he turns, they're suddenly behind his back.
Attic Girl - S1-E17
Other mistake: When Stephanie shows her chainsaw wound to Sam, it is bloody and grotesque but when Flower, who was mauled by a bear, showed Sam her wounds, they were mere scratches with no trace of blood.
Farnsby & B - S1-E18
Other mistake: The ghost in the Farnsby's house knew Ronald Reagan as an actor but in 70 years she didn't know he was elected President even though she would have heard about it from people who lived in the house during his terms.
Revealing mistake: Hetty's reflection is in the octagonal mirror, Issac's reflection is caught in the window he is standing next to and Thorfinn's reflection is in the dressing mirror he passes.
Suggested correction: Where was it established that the ghosts' reflections aren't visible?
It doesn't make sense that the ghosts would have reflections or even cast shadows for that matter, it indicates they have a physical body to block or reflect light which we know isn't the case.
I'd argue if we the audience can see the ghosts, there's no reason why we can't also see their reflections. Other people can't see the ghosts or the reflections. It's suspension of disbelief or a visual narrative tool of sorts. It's different from vampires, say, which generally aren't meant to have reflections at all.
That makes a valid point but based on the "mistake" that started this, I can see why that person thinks reflections are out of context with every other ghost movie out there, like in Beetlejuice where Gena Davis moves the horse in the mirror and she isn't visible. It wouldn't be as good a scene if she was reflected in the mirror too.
Light reflecting off objects is exactly why things are visible. So how can Sam can see them if they're not reflecting light off their bodies? They also can't interact with their environment, so it doesn't make sense that only Sam can hear them because that means they're vibrating the physical air around them. It doesn't make sense that they can walk through walls but sit in chairs.
The whole plot of the show is that only Sam can see/hear them because she had the near death experience. From what you are saying about air vibrations, Jay should be able to at least hear the ghosts but since he can't, its implied they are invisible to, and unheard by, living people. They are manifestations of energy, hence why some can pass their powers onto living people or turn on/off lights, and energy is invisible to the naked eye.
I understand the plot. My point was nothing makes sense if you use physics as we know it, so the mistake isn't valid. Because being "manifestations of energy" doesn't explain how Sam can see and hear them (not the why) or most anything else they do. But since it's a fantasy with its own made up rules, there's nothing to prevent the ghosts from having reflections, no matter what you want to assume they are.
I don't know how many people are in on this, but I'm loving this debate! I do agree though that the ghosts should not have reflections, they're supposed to be invisible unless you have the gift like the lady does.
Ghost Father of the Bride - S2-E19
Factual error: Crash is shown sitting in the TV room at night, but he is watching The Price is Right which is on in the morning in the north-east.