When riding into town the stand in for Jessica is wearing two red scarves on the sides of her shirt, but on the next shot when Jessica's reached the middle of town the two red scarves have vanished.
The rear-view mirror in the remote-control car appears and disappears throughout the episode. In particular, when Jessica is trapped in the car, interior shots show no rear-view mirror, just a mounting plate on the windshield where it should be attached, but in some of the exterior shots of the car, the rear-view mirror is visible.
In all the driver-less car action scenes, the car has huge headrests on the seats (to hide the driver). In close ups, the seats have normal headrests.
The shoes Jessica is wearing when she first meets Katie on the porch at Daniel's house change when they meet him in his work room moment later.
When the door on the driverless car closes , the window is down , but when the car starts to drive away , the window is up .
Toward the end of the episode when Jessica and Ethan are about to play the driving arcade game, Jessica walks past a book stand. But the books are all upside down.
In the "out-of-control car" sequence, about half-way through the episode with Jessica at the wheel, all of the action takes place with the three vehicles travelling in convoy from right to left. But the clip taken from the air (pre-drone era... helicopter?) has had to be reversed for this... look closely, and it can be seen that all of the visible vehicles appear to be driving on the LEFT, British-style.
When the driver less car is running though the picnic there is something visible sticking out from the left rear bumper area.
When the driver-less car is seen at the picnic, you can see the silhouette of the actual stunt driver driving the car.
Jessica drops the tomatoes into the bag from the top instead of setting them into the bottom, like someone who notices details would to avoid bruising them.