I wanted to find another example of the lack of quality control, so I just searched on Amazon for full grain leather belts. I opened one of the cheaper options for $10 and the description says "100% Full Grain Leather". That seems unlikely given the price, so I checked the reviews and there are photos of the belt flaking and peeling, which makes it quite clear it's not full grain leather. One of the reviewers also says the belt is stamped with "Genuine Leather", which once again confirms it's not full grain leather.

So, Amazon sells a belt that is literally described as "100% Full Grain Leather", but it's simply not. But, somehow that's fine.