According to some research I just published in the Journal of Agricultural and Resource Economics with a former graduate student, Kate Brooks, who is now an assistant professor at the University of Nebraska, the answer is "yes."
Our research suggests caution in using people's shopping behavior (as, for example, indicated by grocery story scanner data) to infer which public policies they may or may not support. In the particular application we studied, people were willing to pay large premiums to avoid milk and meat from cloned cows when asked what they wished to buy when shopping in a grocery store. One might conjecture from this behavior, then, that the consumers would approve of a government ban on use of clones in meat and milk production.
According to our research, that conjecture would be wrong. The majority of consumers did NOT favor a ban on cloning in food animals. In fact, most people would demand compensation if a ban were enacted (rather than be willing to pay to have the ban). This finding defies many of the explanations often given for differences in voting and shopping behavior, such as the consumer-vs-citizen hypothesis or the hypothesis that consumers perceive the existence of externalities. The behavior is more consistent with the notion that people have an option value (they don't want to get rid of a technology that may produce some promising result in the future even if they don't want it now) or that people respect the freedom of others to arrive at their own choices even if they happen to be at odds with one's own preferences.
The other interesting thing about our finding is that is exactly the opposite of what has been observed in other food issues. For example, in California, 63.5% of voters voted in favor of Prop 2 in 2008 to effectively ban battery cages in egg production. Yet, the retail market share of cage free eggs is less than 5%. In this case, shoppers aren't willing to shell out the extra bucks for cage free eggs in the grocery store, but they enthusiastically voted to ban the product they normally buy in the voting booth. Why? Hard to say. My feeling is that the costs are much more salient in the store than in the voting booth. Another possibility is that the universe of voters is different than the universe of shoppers (all voters shop but not all shoppers vote). There are, of course, other possible explanations.
Gaining a better understanding why people behave differently when shopping and voting is a key area of future research for food economists. And, the fact that people often behave so differently in the two environments represents a key challenge for food economists who conduct regulatory cost-benefit analysis and advise policy makers.