Studying compliance, in terms of the business responses to legal rules, is notoriously difficult. This paper focuses on the difficulty of capturing the behavioral response itself, rather than on difficulties in explaining compliance and isolating particular factors of influence on it. The paper argues that existing approaches to capture such compliance, using surveys and governmental data, run the risk of failing to capture compliance as it occurs in the reality of day-to-day business responses to the law. It does so by means of a unique ethnographic approach to study compliance. Drawing from data of deep participant observation about responses to legal rules in two small businesses, the paper finds that in this context there is Compliance Dynamism. This means that compliance varies for different rules, it varies over time, and businesses learn from one response to the law to the next on a daily basis. Compliance is also situational, and there is an Indirect Observer Effect, where the way compliance is measured, especially when using data derived from inspections, shapes what compliance is observed and what is not. Therefore, compliance should be captured not as a singular state but as a string of reiterative processes that occur in their situational context. And this fundamentally challenges most existing methods to capture compliance and thus our understanding of what compliance occurs and what may shape it. In its conclusion, the paper draws out the implications this has for studies that seek to find simple and usable findings about compliance.