Operation Ruthless/The Vacant Lot - S1-E7
Continuity mistake: In Operation Ruthless, the pedal in Helga & Phoebe's bumper car changes color from black to gray to black between shots.
Operation Ruthless/The Vacant Lot - S1-E7
Audio problem: Operation Ruthless: When Arnold first starts repeating "Hi Ruth," the shot cuts to Gerald as he says, "Stay cool, Arnold." Arnold can still briefly be heard saying his line, but his mouth doesn't move. (00:03:42)
Operation Ruthless/The Vacant Lot - S1-E7
Continuity mistake: Operation Ruthless: When the Cheese Festival is first shown, Arnold and Gerald are standing at the bumper car ride, but in the next shot, they are suddenly standing in a different location, which seems to be at the green building from the beginning of the episode. (00:03:12)
Operation Ruthless/The Vacant Lot - S1-E7
Revealing mistake: Operation Ruthless: When Helga and Phoebe are chasing Ruth in the bumper car, when Ruth's car stops and Helga looks back at her, Helga's right lower leg is incorrectly layered over the bumper car seat, and Phoebe's legs are colored black. (00:08:11)
Operation Ruthless/The Vacant Lot - S1-E7
Continuity mistake: Operation Ruthless: When Helga and Phoebe's bumper car flies into the air and lands on the hot dog truck, as the people start to run away, watch for one person that disappears from the shot, then reappears, and his shirt changes from green to orange. (00:08:36)
Answer: The show is based in present day times. Plus most cars aren't old fashtioned, I recall seeing a limo and not to mention a cherry picker, etc.