How widespread is the problem of fake SD cards? - Quora
How to spot a fake Sandisk card | GBAtemp.net - The Independent Video Game Community
Warning to anyone buying Samsung SD cards off of eBay. They are made in Korea, so always check the back of the card (real on the left, fake on the right) :
Warning: Watch Out for Fake Memory Cards on eBay - The National Photographic Society
Micro SD & SD Card. Is my SD Card GENUINE or FAKE ? Testing Service. Test 128GB | eBay