Don't think of it as bribery but as an incentive for people to get off the fence.
My favorite though was a car dealership in NC that was giving away a free SHOTGUN with every purchase of a truck. Talk about target marketing.
Promotional gimmicks are a fact of marketing in all facets of business. I would rather not have to mail in a $100 rebate for my new laser printer, and just have Staples give me the better price at the register. I would rather not have to use my discount card at CVS Drugstore or Safeway, and have them give me the better price at the checkout. I think I should not have to go to Best Buy today for their one day sale on Plasma TVs. I think Best Buy should let me buy the Plasma at $500 off tomorrow, instead of it being the "Sunday Special"....If Best Buy can make money on the deal on Sunday, they could on Monday, too.
Promotions, gimmicks and incentives gain attention and bring about results. While most of us claim that we would rather have the quality product and a quality fair price without gimmicks, our world has taken on this pattern for a reason. What we say we want and how we act do not always travel the same path.
Frankly, the car offer is neither troublesome or offensive to me. If I had a buyer and my buyer didn't want the car, I would write an offer excluding the car. I would probably chat with the listing Realtor to find out if the "gimmick" was effective at drawing attention to the listing