At the start of the movie, a great deal is made of the boom mic that enters the shot. This is ridiculous, because Bolt's view would not be restricted to what was onscreen, he'd have a perfect view of the person holding the boom mic (as evidenced by it not being stable). There's no possibility of him not seeing the person holding the mic either. As Bolt completely and utterly believes the world he lives in, and thinks the situations he finds himself in (saving Penny) are real, someone holding a boom mic would break the illusion for him. In ALL instances in the movie where an outside force (i.e. Dog handler) interacts with him, Bolt never gets to see the person handling him (handler approaches from behind), the boom mic operator however is literally right in front of him.
When Bolt threatens to drop Mittens from the overpass unless she tells him where Penny is, the bus from Speed (1994/I, with 2525 on the roof) passes underneath.