[pawpawdiv9]

It is a game of chance.. and if its a HIGH END card, some dont do it, unless they are well knowledgeage and still some get fooled.
You have to ask, why didnt they slab the card?, or did they? It could came back as altered or trimmed and they are selling it as otherwise.
If these are low-end 2-5 dollar cards, heck it is a bargin if you trust the dealer and are not overstating the condition of the card. In some cases the card you receive is not the card is pictured.
1. Know and trust a reputable dealers, there are some out there.
2. Inform yourself
3. Always ask for advice.