A bit from Michael Erard’s 2001 article on closed captions:
Although Clark accepts the inevitability of real-time gaffes, he deems any avoidable error in the pop-on format unacceptable, and he is easily vexed. He criticizes the sans serif fonts typically used for captions as "typographically debased" (among other things, the spacing of their letters cannot be adjusted, and they cannot render many accented letters and other unusual characters), and he complains that to a foreign viewer, the standard U.S. and Canadian practice of using all capital letters "makes everyone seem like they’re shouting."
The Dish 