I had a chance to talk to my old cog sci teacher about this. He pointed out that your example is extremely similar to the way the the wording of questions can greatly effect survey results, even if the chance doesn't seriously effect the actual meaning of the question or the content of the explicit information provided. In a later email he also suggested that
Tversky, Amos; Kahneman, Daniel (1981). "The Framing of decisions and the psychology of choice". Science 211 (4481): 453–458.doi:10.1126/science.7455683. PMID 7455683.
might be of interest.
There's plenty of experimental work about how humans make poor judgments and decisions, but I haven't yet found much about how humans make poor judgments and decisions because of confusions about words. And yet, I expect such errors are common — I, at least, encounter them frequently.
It would be nice to have some scientific studies which illustrate the ways in which confusions about words affect everyday decision making, but instead all I can do is make philosophical arguments and point people to things like Yudkowsky's 37 Ways That Words Can Be Wrong or Chalmers' Verbal Disputes and Philosophical Progress.
Which keywords do I need to find experimental work on this topic? I tried Google scholar searches like "fuzzy concepts" "decision making" and effect of connotations on choices but I didn't find much in my first hour of looking into this.