Visible crew/equipment: Towards the end of the film, as Snyder hustles Lonnegan out of the room (Spoiler alert!), believing that Hooker and Gondorf have been killed, an extra in a pale grey suit with a red tie stands with his hands up. The shadow of a Sennheiser microphone shows up clear as day on his costume.
Visible crew/equipment: When Robert Redford is being chased by Lt. Snyder, he jumps from a high place to the ground. One can easily tell it's not Redford but a stunt double.
Suggested correction: This isn't a mistake. The person "operating the radio" could easily have switched it off because of the commotion. Lonnegan would simply suppose this is what had happened. He is not going to instantly suspect someone is faking the whole thing.