Who would have thought that tennis balls would have a practical value outside of the sport?
I first heard about the technique to steal cars using a tennis ball in the summer of 1998. A friend of a friend from Italy told me about it. I thought that was interesting and stored it as useless knowledge.
My only comment is that it’s a European thing, not a US. Perhaps that why Adam did not recognize the make or model. (If one looks at the car in the background, one can see the outlines of European license plates.)