AirPods are very commonly swapped with fakes and returned. It wouldn't surprise me if they added a blanket policy requiring ID for all AirPod refunds no matter what.
Apple products and a few other brands go through a different process for returns at Amazon.
Amazon can't verify everything, but for it's own Fire devices it does check S/Ns. Also Apple has it's own system, they do not mess around. I suggest not buying Apple products from Amazon.
Source: I work in LP, but not for Amazon.