So over here every pack of cigarettes has a big label saying 'smoking kills' and might show graphic images that 'prove' that smoking can cause lung cancer, blindness etc.
Given that I don't smoke and hate the smell I'm sure that I'm heavily biased, but I still think that this is a good thing. The government isn't restricting access to your drug of choice, it just tries to make it less appealing.
Labeling water with 'Actually, this is useless' feels like a good idea to me. People that jumped the fence, 'true believers', won't be affected. They shake their head, mumble that The System is broken and doesn't support alternative treatments and .. will continue to buy that shit.
But people that are in need of help might actually read that disclaimer and save time & money.
If you cannot buy real medicine for some reason (how barbaric is that, btw?) I don't think that you should buy overpriced water instead.