Sure. If we didn’t use the double blind method, the scientist’s inherent bias would skew the results.
Maybe, but I'd guess 99% of science does happen outside double-blinds and sometimes with just the tiniest shreds of physical evidence.
Think of a CSI type crime investigation, where agents analyze a bit of hair here, some blood there, maybe a bullet, attempting to piece together a case that can stand up in court.
No double-blind and obvious interest in nailing a suspect, is it fake science?
Answer: not if done properly, but nothing humans do is ever 100% perfect, even I dare say, the best of double-blinds.
You disagree?