Didn't know paper shredders need oil

Last week I went to Office Depot (a fine store) to buy a paper shredder. The lady at check out asked me if I "had any oil?" "What?" I said, not understanding. She told me that her son told her that shredders need to be oiled. She then hands over a bottle of oil and tells me to use it or I might ruin the shredder like she did. I still was unconvinced, saying "I understand oiling my sewing machine, but a shredder?" She said to put oil on a piece of paper and run it through. As she sure sounded authoritative I said, "OK" and let her sell me that bottle of oil. Hmm. Well, so I did put some oil on on envelope plastic I was shredding, so who knows. I don't remember anyone oiling shredders in any of the offices I used to work in, but who know who does what behind the scenes. Thought I'd pass on this office tool advice.