The price difference between enjoying a small beer and a large beer at the Oakland Coliseum is $3. Nevermind that they're both roughly the same amount of liquid.
A YouTube video from an A's fan shows that pouring water from a large portion into a small glass causes no spillage.
(Why anyone would opt for a small beer at a baseball game is beyond us, too, but we digress.)
A similar phenomenon occurred up the coast in Seattle, where stadium officials admitted that the small and large sizes both held 20 ounces.
(So that's why people bought the small size? Free beer! Genius.)