On the American Dialect Society's mailing list, someone posted this story from The Onion:
William Safire Orders Two Whoppers Junior
NEW YORK — Stopping for lunch at a Manhattan Burger King, New York Times ‘On Language’ columnist William Safire ordered two “Whoppers Junior” Thursday. “Most Burger King patrons operate under the fallacious assumption that the plural is ‘Whopper Juniors,’” Safire told a woman standing in line behind him. “This, of course, is a grievous grammatical blunder, akin to saying ‘passerbys’ or, worse yet, the dreaded ‘attorney generals.’” Last week, Safire patronized a midtown Taco Bell, ordering “two Big Beef Burritos Supreme.”
To which one poster, not realizing the satire, replied in seriousness:
But of course the back-to-back sibilants in Burritos Supreme would probably
not be heard as pluralizing the noun, so Safire might have been heard as
“talking funny,” i.e., not marking the plural after a quantifier (ESL
speakers do this all the time).
Heh. (and I'm guessing that ESL means “English as a Second Language” in this case)