Visible crew/equipment: When Oliver jumps out of the window of Adam Hunt's office, you can see the safety rope at the bottom.
Arrow (2012)
1 visible crew/equipment mistake in season 1
Starring: Katie Cassidy, David Ramsey, Stephen Amell, Colin Donnell, Emily Bett Rickards
The Magician - S3-E4
Revealing mistake: When Oliver meets Thea at the Grind and Jot Cafe (Which looks unsurprisingly like CC Jitters) you can see the cups on the table are from CC Jitters. (00:20:50)
Darkness on the Edge of Town - S1-E22
Oliver Queen: Roy! We haven't met. I'm Thea's disapproving older brother.
Trivia: Although Laurel is a couple of years older than Sara, Katie Cassidy is only about a month older than Caity Lotz.