When Barney switches our the card decks there are three pairs of red decks in the front and three pairs of blue decks in the back. He places two blue in back and one in the front, and then two red in front and one in the back. He may have done this to be sure that Alex Lowell would notice the card swap.
When Alex and the judge get in the car the hood is down. When they exit with the wire to start the ignition the hood is suddenly up even though they never touched it.
When Briggs is looking through the pictures of potential team members in the opening, he rejects one picture of a guy with glasses, which is seen lying to the side on the table as he continues to look through the pictures. He then rejects a second picture, but when the view of the table is shown again, it only shows the guy with glasses; the second picture (which should have been on top of it) is absent.
As dirty and bumpy as the rolled piece of reflective material was, it could have never reflected as perfectly as it depicted. A real glass mirror was used when barney did the trick.
When preparing to start the car to see if it was going to explode, it should have exploded as soon as the wires were being cut (the wire cutters would complete the circuit). But it didn't explode until the stripped ends of the wires were touched together.
There was no speaker in the drive in car speaker box used for introducing the mission. It was only stuffed with rags which were most likely used to create the self destruct flare-up.
When the dog first discovered Barney camouflaged under the table, the reflection of the dog could be seen on the mirror material, but the next shots show no reflection of the dog where the mirror material and Barney were supposed to be.
When the group is making the stripper decks, Barney is shown shaving the edges off the cards that need to be pulled to the top of the deck. Explicitly the ace of spades. He was supposed to shave down the other 43 cards so the strippers could be grabbed.
New decks of cards come in a uniform order A-K suited 4 times. When Lowell opened the stripped deck and checked them for marks, they were in an order that showed they had been shuffled. This might have been done intentionally by the team.