I've recently received what turned out to be a counterfeit memory card supplied by 'stardeals_uk' based in Ilford and selling on ebay. It was supposedly a sandisk card, which produced raw images with thin purple horizontal lines or large purple areas. Having supplied pictures and details of the card to sandisk, they have confirmed that it's counterfeit. Some indicators for anyone who doesn't know, are a yellow locking tab, no serial number or 'Made in China' on the back, and uneven contacts. There are other signs but these are easy to spot. Also it cost £17 rather than £28. Sandisk will be confronting the seller who hopefully will be taken to task.
Hope this is of some use.
Hope this is of some use.