This isn't a traditional lease, though. If you read the original article about the "new" financing product, you are purchasing the car. This makes you eligible for the tax credit(s).

After three years, you have the option of (a) doing nothing and paying nothing besides your normal payments. After all, you bought the car. (b) selling the car back to Tesla. You are not obligated to sell it, but if you want to, Tesla is obligated to buy it back. If you sell it to them you then pay the penalty.

So this hypothetical salesman need only not sell it to Tesla, or sell it to someone else after the tax credit period (which I believe is amortized over three years or something).