Visible crew/equipment: When Shawn and Gus gets out of the car at the Mausoleum Parking, you can see the camera man reflected in the mirror inside the car.
Continuity mistake: A man attacks the judge by running out of the shower. When he runs through the shower, a shower curtain is draped over him. For most of the scene it is over his head, but when he is dragging the judge into the shower, the curtain has moved off of his head and is even gone completely in one shot, perhaps to make the actor more visible.
Character mistake: When Shawn is checking Ed's book of valuables, the crown that Shawn thinks Despereaux will steal, has a listed value of "950,000 - 1,000,00,000 USD." I guess it's really, really(!) valuable, enough that a whole new numbering system was made up for it.
Continuity mistake: When Shawn and Gus are driving the boat at night, we see the coordinates on the GPS tracker - two seconds later (real time, as they are talking), the coordinates have changed; now they are about 37 miles from where they were, so they must have hit 65,000 mph for those 2 seconds. In case my math needs correcting, the first set is 34 06' 50.25" N x 120 17' 41.31" W and the second set is 33 57' 40.21" N x 119 35' 56.58" W.
Continuity mistake: When Shaun calls the first student up to the board to write a number, firstly the written number is 6.00214, which is an incorrect Avagadro's number, but it is not always this incorrect number. At some point during filming somebody changed it to the correct number: 6.02214, and you can see the number actually changing back and forth between the two numerous times during this scene.
Factual error: Shawn reports that one of the attendees of the speed dating session drives a 2004 Trans-Am. The Trans-Am was discontinued in 2002.
Continuity mistake: When Shawn sees the box with the dead doctor's files, Regina Kane's file is visible halfway back in the box. He then tells Gus, "All we have to do is find Regina's." (Which he was looking straight at, but let's call that a character mistake.) A few moments later, we cut back to Shawn and Gus and Shawn finds her file in the front of the box.
Visible crew/equipment: When Shawn and Gus gets out of the car to start digging for the money, you can see the boom mic reflected in the back window of the car.