This study explores the tension between the standard economic theory of preference and non-standard theories of preference that are motivated by an underlying theory of framing. A simple experiment fails to measure a known preference. The divergence of the measured preference from the known preference reflects a mistake, arising from some subjects' misconception of the game form. We conclude that choice data should not be granted an unqualified interpretation of preference revelation. Mistakes in choices obscured by a possible error at the foundation of the theory of framing, can masquerade as having been produced by non-standard preferences.