Won't they just receive bad feedback on the detail of "Shipping higher than actual cost" resulting in their fee's rising?
Actually ebay has a stupid policy that you can't leave neg feedback unless you pay for the item.
I know this b/c I fell for one of these auctions in the past, where the seller sold a $200 brooks giftcard for $25 but had $200 shipping. I didn't catch it b/c he didn't mention it in the description. When I contacted ebay, they told me not to pay him and they would remove the auction. I left him neg feedback, but it was removed b/c he filed a reverse complaint that I didn't pay for the auction, even though that is what ebay told me to do. In the end, the auction was removed but so was my feedback.