The ubiquity of mobile devices has resulted in more opportunities to interact with more people than ever before. Given a finite capacity for interaction with others, people commonly manage their availability by limiting others' access to them. Prior work has demonstrated the importance of doing so in a relationally sensitive way and identified the butler lie, in which deception is used to manage availability, as a common linguistic strategy. Two key limitations of existing exploratory work, however, are limited samples of primarily students and a focus on media properties in understanding ambiguity that enables butler lies to be plausible. This paper aims to address these issues via a broad field study of deception and butler lies using a novel message-sampling method employed via a custom mobile app. Results show clear evidence of butler lies occurring in a broader population, with some gender differences; and urge adoption of a multi-level framework for understanding ambiguity that also includes private information and infrastructure-level attributes of interaction media.