Deliberate mistake: In the shot where the camera zooms in on the car, after they realise they are standing on a train track, it is obvious that the car would be hit by the train even if they managed to change tracks. The car's hood is parked right above the other track. (00:23:45)
Deliberate mistake: When Sunny picks up the Scrabble letter, you can hear her biting a piece of it. But when she places it on the board, you can see it hasn't been chewed on. It looks exactly the same as when she picked it up. (00:03:45)
Deliberate mistake: When Violet and Klaus have the anchor on the three cans they use to roll it on, just before they tip it over the edge, it is obvious the anchor isn't a real anchor. It's too light. When they keep pushing it back and forth, it should tip over because of the weight if it was a real anchor. They shouldn't have been able to handle it like that. (01:01:45)
Answer: A magnifying glass concentrates all the light that goes through it at its focal point, and it is this focal point that needs to be placed on the object which one wants to set on fire. The distance of the focal point to the lens depends on the magnifying glass characteristics, and it is more than likely that Count Olaf chose a glass where the focal point would be situated exactly "37 blocks" away from his house, that is, at the Baudelaire's mansion. When trying to set on fire an object much, much closer, the glass would concentrate much, much less energy, and would only be able to set on fire easily burnt objects, such as thin paper.
AnthonyA