In US-Gambling, the Appellate Body held that an origin-neutral prohibition on remote gambling (which is how they mostly viewed the United States law) was "in effect" a "zero-quota", and that such a "zero-quota" violated GATS Article XVI:2. That holding has been widely criticized, especially for what critics refer to as the Appellate Body's "effects test". This article argues that the Appellate Body's "in effect" analysis is not an "effects test" and is not the real problem. The real mistake is regarding a so-called "zero-quota" as a quota under Article XVI. That is inconsistent with the ordinary meaning of the word "quota" in such a context; it is at odds with the object and purpose of Article XVI; and it is likely to reduce Members' willingness to make concessions.
Regan, Donald H. "A Gambling Paradox: Why an Origin-Neutral 'Zero-Quota' Is Not a Quota Under GATS Article XVI." J. World Trade 41, no. 6 (2007): 1297-317.