We present a study that investigates whether the transparency of the data acquisition technique can work as a heuristic when making evaluations about data protection and sensitivity. The study (N = 40) compares an explicit data acquisition technique (questionnaires) with an implicit one (eye-tracker) and varies also the actual sensitivity of the data collected (popularity evaluation vs. usability evaluation). The results suggest that, when judging general data sensitivity, the transparency of the data collection procedure might work as a heuristic; instead if more specific judgments or decisions are asked this effect is not observed. Implications are discussed.