When asked to estimate the carbon footprint of a bundle of low carbon footprint and high carbon footprint items, people typically report a lower value compared to estimating the high carbon footprint items alone. This finding is called the negative footprint illusion. Previous research suggests that people might be made less susceptible to this effect depending on whether they are asked to evaluate how environmentally friendly or how environmentally damaging the items are. In the current study, we used large instead of small stimulus sets (i.e. a more powerful experimental manipulation than that in previous research) and show under these circumstances it does not matter whether participants are required to make friendliness or damaging estimates. The role of attribute substitution along with other conceptual and methodological issues to the negative footprint illusion are discussed, particularly in relation to a recent paper by Gorissen et al. [2024. Green versus grey framing: Exploring the mechanism behind the negative footprint illusion in environmental sustainability assessments. Sustainability, 16(4), 1411].