In the US, some folks are shot drinkers. They slug down liquor in one gulp. They were raised to think whiskey tastes nasty, and they want to swallow it fast, like harsh medicine. That’s a waste of good whiskey, IMO, and I never understood it. Maybe that’s why Jagermeister is popular; it tastes like cough medicine. Shot drinkers probably wouldn’t notice if a whiskey was spiked with a little rubbing alcohol.
An acquaintance of mine got away with watering the spirits all one summer when he was young. Him and a friend were doing it to cover up serving free drinks to girls. The “free drinks” probably weren’t ilegal at the time (that was just theft from employer), but watering the spirits was. Anyway the free drinks attracted the girls, the girls attracted the guys, and from his account that bar was /hopping/ all that summer.
Had one tense afternoon when the excise was in testing, but they only did the main bar (beer for blokes) and never got onto the kids bar.