Broaden the data for each user to help send them in the appropriate direction for new surveys. For instance, I'm vegan and I keep getting surveys about meat eating. Usually, it stops after 5-10 questions. I think this would also help with the honesty issue that you folks are clearly up against. People don't go to your site to get constantly redirected. They want to answer surveys. Eventually, you figure out how to carefully walk through the surveys that aren't the best fit for you to get the reward. I haven't done this because I tend to have pretty strong feelings on certain issues. I AM CERTAIN that it happens though.
Thank you for your feedback!