Revealing mistake: Mason brings his unnamed son to the lake and acts like he is going to drown him. The baby is noticeably a doll in all but the scene where he kisses it. It is obvious from the way he is carrying it as well as the lack of movement.
The Bad Beginning: Part One - S1-E1
Revealing mistake: Near the end of the episode when the Baudelaires are in bed, the camera goes outside and pans down the front of the house. Once it reaches the next set of windows below the Baudelaires' "bedroom", the camera wobbles slightly.
Revealing mistake: Some of the punches don't land when Linc and C-Note are fighting the bad guys in the garage. This despite the sound indicating they are landing.
Revealing mistake: The scene is set in Boston, MA, USA, but at a murder location, a European-style circular power outlet is visible through the glass doors at the bottom of the concrete wall. (00:01:20)
Revealing mistake: June goes to an airstrip to fly to Canada, but all the abandoned aircraft on the field are ex Canadian Air Force, meaning it was probably filmed in Canada.
Revealing mistake: Supposedly in Liberia, the team takeoff in a helicopter. However, when they take off, the camera reveals the airfield, where several general aviation aircraft are parked. This is highly unlikely to be in Liberia, also the night lights seem to be somewhere in Cali (perhaps LA)). (00:27:20)