EBay auctions often end up in glossy catalogs. There are numerous examples. No way of knowing about auction house employees and their trolling habits, but without a doubt, auction house consignors troll eBay and maybe this forum.
Cliff Hagan hoop jersey, Robisch Laker jersey, etc.,etc. These are recent examples off the top of my head.
There is nothing wrong with finding a good deal and turning a profit.