Here's a first-hand account from Britain:
In a last-ditch attempt, I run up to someone with a clipboard and beg. "I'm not an actor, I'm a journalist! I'm writing about what it's like to audition! Please just let me have a go." The man looks at me and laughs. "We've already had George Lucas's nephew and someone pretending to faint. Go home, you're not going to be seen."
We're reminded of this SNL classic: