Not only do they violate peoples' individual freedom, they harm the economy:
"The more laws governments pass, the more they are subject to the oldest law of all: the law of unintended consequences. And smoking bans are having bizarre consequences across the world…In Britain, where smoking in enclosed public places became totally illegal in 2007, beer sales are down by 10 per cent; analysts attribute half of that to the smoking law. Pubs are now closing at a record rate of 36 a week....There are similar reports from Ireland, where the broadcaster Gerry Anderson said bars now had the atmosphere of a dentist’s waiting room. In France, more than 500 of the 40,000 cafés and bars disappeared last year. Again, the ban is largely blamed. And in France, the climate is more conducive to sitting outside with a Ricard and a Gauloise. Latest figures suggest there has been no effect at all on tobacco consumption in Britain or Ireland. And anecdotal evidence is that kids are now staying out of pubs, heading for any open spaces they can find, getting bladdered on cheap supermarket lager and smoking their heads off."
Friedrich von Hayek is vindicated again--government planning and intervention in the economy will ALWAYS be problematic, because big government can never grasp all the consequences, intended and unintended, that its policies will have upon the economy.