I believe that there is evidence that the higher the heat of the burning, the worse the carcinogen production, and that might be one reason why cigarette smoking is especially dangerous (only one reason - inhaling the smoke is a major factor here as well).

So Fred Miller's idea might actually make a lot of sense - water pupes of course lower the temperature of the smoke itself, but that's a different mater. People often assume when they see water pipes that they are just used for pot, but they have traditionally been used for tobacco as well.