I see them all the time on dealers coins. This one was amusing because it said "same as two pizzas". http://www.ebay.com/itm/1909-S-Silv...57?pt=Coins_US_Individual&hash=item4d05dcd13d
I avoid such sellers who plaster their 2x2 or slabs with such tackiness. It's a marketing gimmick and the stickers distract from the actual coin itself.
I scroll faster when I see these disgusting stickers in search results. Clearly designed to attract idiots who often attend eBay to make high bids on ****ty coins. The stickers look like they were purchased, but they can also be printed with special software and any home printer.
I don't go to ebay often to buy a coin. But when I do I always choose one whose cost is the same as two pizzas.
It's a booster like Wow!!!! or Look!!!!!. Do you remember your "Grade this Chief" IHC? Do you remember i said I knocked two grades off for calling it a chief? That wasn't meant as a joke or an insult. I assumed you were boosting it. If I were to bid on a coin I thought was being boosted (which I wouldn't) I woud not trouble myself trying to figure out why I would just adjust my bid two grades lower. But that might not clear minimim or some fool would easily out bid me. Which is why I don't bother with those kind of auctions.