Why would I buy a car from a dealer (that I otherwise wouldn't have) because he gave someone that I don't’ know a free car, because she brought in some yellow paper? I think I'd go to a dealer that could still afford to cut me a deal.
I presume you don't own a car dealership.
It depends on the area, the market there, and the people, but in this neck of the woods, "honesty" as percieved by the people who buy cars goes a long way.
It could have led to significant sales, especially if they sell used vehicles as well.
You might want to check your math before getting quite so irate.