At least the lab data should be confirmed by observing comparable real-life checkout scenarios. Managing variables would be challenging in a genuine retail set

At least the lab data should be confirmed by observing comparable real-life checkout scenarios. Managing variables would be challenging in a genuine retail setting, but it probably can be accomplished well enough. The fact that the outcome will vary in different store environments isn't a trivial factor in evaluating the claims of the experiment. IOW the findings may apply in some cases but not others, which is an important kind of detail to consider.