That's funny, because all of the body shops around here used to say way over half of the cars they worked on had deer whistles.

Let's see, they sell several thousand whistles @$7 and promise to refund your money if you hit  a deer.  How many people are going to take the time to return a $7 whistle.  I'd make that deal all day. Now, if they promised to fix my car then I would believe that they might work.