I'm not sure if the article I linked to was even the same one that I read a while ago, it was just the second thing that popped up in Google. I regard it more as a curiosity anyway.
I think it would have been better if they had made that experiment in a more neutral setting (psychology students perhaps), the aspect of the political parties is distracting. The main point is that nudges can go wrong.
I'm also having trouble parsing the tables in the original paper, but it appears that there are groups with a worse treatment effect (e.g. college educated with above-average use) that the authors did not highlight. Perhaps this is a misreading on my part?
http://www.econ.ucla.edu/costa/Nudgew15939.pdf