I used to work for one of these companies as a truck driver / shredder. We had special security dumpsters that we leased out to businesses around town that only we had the keys too. When the box was full we would drive on over to the business, hook the dumpster up to our truck, unlock the box and press a button. The whole dumpster goes inside the box and destroys everything leaving no evidence and the dumpster comes back out. You put the padlock back on and carry on with your day. Never once did I see any personal information, or have any idea what kind of information I was getting rid off. So in that regard these people are telling the truth, they probably didn't know what they were shredding.