[elbasti]

Actually, a lof of blind trials are hard to run precisely because it's so obvious if you're not on the placebo side.

Like...nobody could ever take a macro dose of LSD or mushrooms and not know it.

[foolswisdom]

That's because it's obvious due to effects other than the one you're trying to observe. Which is of course the case when you're dealing with psychedelics (and of course many other drugs).