They do the same thing with Latin names of people in the news. They'll be reading a straight story with a perfect Midwest non-accent about the Red Sox, for example, and get to "Manny Ramirez" and "David Ortiz" and read those names like they were working for a news station in the Dominican Republic.
Oprah Winfrey used to be a newscaster, and she talked about using ethnic names once, while on the air. She breezed through the hispanic names easily, but got her tongue twisted when she pronouned Canada... using a hispanic accent. She sounded like a fool.