An unblinded study would not be able to account for placebo effects.
Why wouldn't I experience placebo effects if I started drinking as the result of controlled trials which suggest that drinking will reduce all-cause mortality?
I want to know the effectiveness of the combination of chemical effects and placebo effects from the treatment I take, not the effectiveness of an outwardly similar treatment that has had significant changes made for the purpose of getting results different from the results I should expect.
My roommate recently sent me a review article that LW might find interesting:
Personal observation says that LWers tend not to drink very much or often. Perhaps that should change, to the degree suggested by the article?
Full article here.