Well yes Carl the owner has
Well yes Carl the owner has already paid for the electricity. It is NOT free. you just don't pay when you charge. Tesla adds a $2000 surcharge to the Model S. This $2000 per is used to build the Supercharger stations and pay for the electricity and maintenance ( of the network).
The Tesla model S is the best ALTERNATIVE to gasoline. If you coordinate your bathroom and meal breaks with charging events then there is NO wasted time. Its just a matter of tweaking you travel habits.