Radio personality Neil Boortz totally scared a rube one day when he convinced the guy his well was full of it and he needed to call the health department to fix it.
Penn and Teller did a good bit on this on their show, "Bull....". They actually got quite a lot of people at an environmental rally to sign the petition banning it.
Boortz actually had the manager af the Atlanta Water Dept call his show and totally denied that there was any di-hydrogen monoxide in the cities water supply and was very insulted that Boortz would spread that kind of rumor.