Requiring psychedelic studies to be blind is πππ. Come on people. Even if it were possible it's ridiculous.
"We wanted to test whether people enjoy being in a sunny meadow or a dim office better. But obviously people will know which one we put them in. So to overcome bias we enclosed each person's head in a lightproof, soundproof cube. The resulting study found no difference in preference between the two environments. That's Science."