Continuity mistake: Red is at a carnival, following her dad. In a shot from behind he's holding a cup, which disappears in a different angle.
Continuity mistake: Red is barefoot for a long period in the movie, but when they run to the boat she's wearing barely-visible slippers, presumably to protect her feet while running outside.
Factual error: The scene where Pluto gets burned takes place at the Santa Cruz Natural History Museum, directly east of the Beach Boardwalk. In order to drive to the boardwalk in the scene immediately afterward, the Wilsons would have to pass through the line of Tethers holding hands.
Continuity mistake: When Zora is bashing the girl's head in with the golf club, blood is spraying everywhere, except magically none gets on her shirt. But then later it's covered in blood.
Continuity mistake: When Gabe's on the bed and Adelaide is saying she wants to go home, there's some blanket bunched up between his legs which disappears in other shots.
Other mistake: Katie cuts herself with a pair of scissors but when the girl hits her there's no mark there.
Continuity mistake: When Gabe and Josh are talking on the beach about the things in the boat, Josh mentions the flare gun. Gabe is looking off to the side, but when angle changes as Josh says he knew he'd forget it, suddenly Gabe is looking straight ahead. (00:24:25)
Continuity mistake: When Red gets out of the car to confront evil Jason towards the end, her shoulder is uncovered from the shot inside the car, but instantly covered in the shot from outside.
Answer: The project was abandoned, but they obviously kept the tethered ones alive. This may have been out of some sense of compassion, or because there was a possibility they would be useful in the future.