They did this here in NY, mainly because of Four Loko. Fact of the matter is, they're marketed to kids, have as much alcohol as wine, and have killed a few people. It's nice that they have the foresight to keep this restrained to beverages that add caffeine as a separate ingredient, though.
They're marketing to young adults but if they were marketing to kids then bust them for that. Anyway, you can't legislate stupidity imo this law is silly.