If they're on Managed Payments that not as much, but they'll be out shipping and 30 cents which can easily amount to $30. And a negative review for an illegal activity on the buyers part is just shady. If they're still on PayPal, then they loose an extra 3%, so it could rack up to $60-80 easily depending on the cost. Likewise, whether they can return the item is up in the air to especially if the buyer opened/damaged the item. If you have a 14 day return window and shipping time takes 4-5 days each way, that uses it up.
The only crime here (and only thing morally wrong) is screwing someone over because they have something you want but not at the price you want. Its like burning down a business. Yes, if they have insurance they might have most of the costs covered, but not all. And they'll be out of work for a long time and rebuilding and dealing with insurance nonsense takes a lot of personal time.
Throwing tantrums that costs people time and money because you couldn't get your toy is okay if you're 10 years old, but I'm doubting the people buying these GPUs are 10 years old.