What is? To sell a product but not want to disclose the company you work for? Maybe it's common if you work for the Russian mafia.
I think the fact that he will not say who he is working for is VERY suspicious, and the guy should definitely be reported.
I would go further than reporting him. If possible, I would also grab a camera and take his picture, if he's still around -- just to discourage him from hanging around my neighborhood, but also as a record.
I wish I'd thought of that yesterday!