Although setting is supposed to be in San Francisco, the Vancouver Lookout is clearly visible reflected in the window of the public use car being borrowed by the sliders.
When Henry the dog is jumping at Arturo and he tells him to "Get down you loathsome creature", Quinn replies, "At least he's not biting you," but his lips clearly say, "At least he's not humping you."
Quinn crashes a car near the end, and the group has to run away. When Quinn runs, his jacket flaps up briefly and a mike pack is seen on his belt.
When Quinn and Wade are horseback riding, Wade tells Quinn to keep his weight on the balls of his feet. Anyone who horseback rides, however, knows that it is just the opposite. One keeps one's weight on one's heels.