Do Jam-Proof Shredders really exist?

Let's face it, shredders jam! I mean, how many times have you had to wrestle paper from the death grip of a shredder?  Fellowes stakes a claim that their new desk-side shredder is jam-proof. Suffice it to say, the editors of Popular Mechanics wanted to put this shredder to the test! What they did discover is that this shredder isn't a power house of a shredder (but Fellowes never claimed it was), but the secret to being a jam-proof shredder is in it's mechanical structure; if one tries to put any thick documents or say, a sheet of metal, the shredder will stop. Thus, allowing one to pull them out without encountering nary of a problem!