Yeah, people really don't know what new means. If it is tested it's not new!!
I got burned by a guy on Yahoo auctions Japan selling a "new" copy of Symphony of the Night for Saturn. Natually I bid more than I would for an open copy. Got an opened copy that had some light scuffs on the disc. How is that new?! He said he had opened it to check the contents... What BS!!
For older systems I can understand why a seller would want to test it avoid the hassle of something arriving DOA. If you are smart you will use accessories that you have lying around for the test so you just need to take out the system itself.
But when you say its new and stuff are missing then try to pull the "but I didn't list it in the description" rubbish you get under my skin.
Hey, you want to buy a new car? What is that, the "new" car I sold you has no seats or windows? Well of course not, I didn't list them in them in the description, now did I?