It would probably be a more effective prank with a bunch of young kids who don’t have a lot of experience drinking and generally act half retarded anyway even when sober.
Adults generally tend to try to not act moronic when they drink, so I imagine that they would notice that it is a lot easier to keep their shit together.
There might be a psychosomatic reaction where they feel a bit more relaxed and uninhibited, but I’m pretty sure most people wouldn’t be falling down stupid.