Interesting but not relevant here - they require a photo of a physical receipt, and they're hand reviewed. Anything is scammable given enough effort though, no doubt.

that’s exactly the amazon scam, executed with a verified receipt and “hand reviewed”. or did you mean, manually moderated? that’s no obstacle.

for amazon the receipt is guaranteed authentic as the product will have been verifiably purchased on amazon. for a 3p site receipts can be trivially fabricated