Hmmm, well I'll take door #3 before going down the rabbit hole with a point many of you might not have considered:
DOOR #3: (oddly it opens, you didn't need a key, the door wasn't locked or rusted shut)
Movies are generally decorated from prop warehouses and studios and production companies maintain a lot of generic locations they can shoot in, renting out apartments, houses, and other assorted things. Even in studios the guys building the scenes oftentimes follow a rather generic formula.
If I had to make a guess your looking at what amounts to a pretty generic "school build" being used for "Kintergarten Cop" with a lot of timeless and generic props. It's quite possible that whoever was doing Silent Hill's locations had some movie experience and used the same cookie cutter in setting up the layout.
Every once in a while you run into cases where if you look you can recognize the same locations and props in various TV shows done by the same people over the years. After all they aren't going to say totally tear down the "Police Captain's Office" and rebuild it from scratch for every single cop show out there. It might get decorated a bit differantly but well... you can see where this is going.
I'm wondering if Konami will ever answer this one, or if they will play it up for fun given the release of the HD Silent Hill Collection and "Downpour" before too long.
Of course it's also possible that they DID imitate that movie when they were making the game and are deciding to give this reveal indirectly though the online fan base (ie "discovered" by fans) as a way of getting attention before the game's release.
DOWN THE RABBIT HOLE (There was no hole here, now there is one)
The best place to hide something is in plain sight, one recurring element of conspiricy theories is the goverment, Illuminati, consortium of multinational interests, or whatever else using fiction to hide the truth. Basically if they make fiction about something very close to reality then people will dismiss it as being made up, and anyone making claims
about it as being an insane fanboy, or someone unable to differentiate between fantasy
In this case if there was a town disappearing people, and it was hard to contain as it leaked out into other places, one of the best ways to hide it would be to show locations from it in movies, and make video games about it. Someone describes that school they could say "hey your describing the set from that movie Arnie did to prove he could act" a movie which nearly everyone has seen and thus could have slipped into the subconscious. Likewise a video game about a killer town where reality is warped is a great way to cover up that one exists because anyone who knows about it OBVIOUSLY played the video games and can thus be ignored as a nut.
This arguement has been made in both a general, and specific, sense about everything from crime, to espianage, to supernatural occurances and horror.
One of the creepier bits is the idea that the current trend towards "found footage" movies that look realistic due to the shoestring budget is largely because of the proliferation of personal recording devices. Someone finding footage of people being haunted, killed in the woods, or whatever could easily be dismissed (perhaps by the finder) as a little heard of movie in the genere, or someone's personal attempt to be a horror film maker.
For example, if I showed you footage of a classic haunting that happened to be real, after the release of things like "Paranormal Activity" would you believe it was genuine even if it was? Probably not. Humans are by their nature skeptical especially when it comes to whole heartedly embracing something that could make them a minority.
According to this theory, the "paranormal investigation" shows are an attempt to hide rising supernatural occurances behind glam. Something happens... they just want to be on TV.
So mebbe, just mebbe, this is all real, and what we're seeing is evidence that Silent Hill, or something similar to it, exists.
Why cover it up? Well, would any goverment want to admit that a lot of stuff like this is out there if it couldn't deal with it? Just imagine what it means for society and the law if the goverment ever acknowleged people could be killed by supernatural forces rather arbitrarly even if it was very rare. There might not be a massive public panic (actually I doubt it, humans are orderly and social) but just imagine what it would mean for crimes like murder if all of a sudden "a ghost did it" could be used as cover. :)
On a final creepy note, ghosts do exist legally. Realtors have to reveal to potential buyers when a house has a history either of bad things happening there OR of reported hauntings and odd occurances. In real life a group of people who are totally oblivious moving into a haunted house is unlikely nowadays, because enough real people found themselves in odd positions and could prove it to get laws passed. I'm actually serious here, kind of surprised me when I was in school... though I imagine it could have since been overturned. I think the example was laws from New York.
Okay well now it's time to climb out of the Rabbit Hole, but it was fun down there wasn't it? There is no reason to get nervous about going outside in the fog for a walk and then noticing the next street corner has a signpost marking it as being named after a famous horror author.... which is odd, because you would have noticed this living in town for years. After all... the truely sane and rational know the mists take you to Ravenloft. :)