There are no laws "currently" is a better phrase. Should Tesla become a serious maker of cars; having one model and a goal of only 35k a year keeps them at the size of Porsche; then they are going to attract attention. That they have received Federal money and their cars are subject to incentives by the federal government and states will put pressure on legislatures to extract "something" from them.
To put their sales goals into perspective, a luxury brand like Lexus can sell over 20k a month. The top five sell a hundred thousand plus cars per month. Chart of August sales is at http://www.autoblog.com/2012/09/04/august-2012-big-jumps-edi...