My client, a fairly big financial company, struck some sort of deal with a radio station. They would be able to use station announcers for a radio spot.
I wrote the spot, which required a character. Needless to say the announcer sounded like an announcer, not the  character I wanted. So I told them they needed to find an actor that can sound like  the character.

Lesson: be cautious with deals using staff announcers. If the spot is just an announcement, you’re fine. But if it requires some acting – get an actor.