In the Electronics section of Amazon's Policies and Agreements, there's a long list of examples of prohibited listings, such as cell jammers, modified Blu-ray players designed to disable region coding, and various other things. Down at the bottom of the list is a brand new entry for "any USB-C (or USB Type-C) cable or adapter product that is not compliant with standard specifications issued by 'USB Implementers Forum Inc.'"
The problem that Leung discovered is that several USB Type-C cables that were being sold on Amazon were out of spec and didn't work properly. One of the main issues is that several cable makers opted to use 10 kΩ resistors instead of 56 kΩ on USB Type-C adapter cables with a Type-A end for legacy devices. That could cause a USB Type-C device to try and draw 3A from an older charger that might only be able to handle 2A or less.
Leung took it upon himself to leave transparent user reviews of cables on Amazon that clearly identified himself as a Google engineer. He didn't shy away from leaving negative evaluations of shoddy cables, though a particularly bad cable ended his crusade when it destroyed his Chromebook Pixel.
It was a Surjtech cable that in addition to using the wrong resistor value also came miswired with the voltage and ground wires reversed. The cabled ended up zapping his system, along with this Twinkle USB PD analyzer.
While a tough loss for Leung, the attention his efforts received led to Amazon's change in policy, which should go a long way towards eradicating the market for USB Type-C cable that are out of spec.
"Really great news, but we all have to continue to be vigilant and call out any bad products we find on Amazon and other stores (both online and brick and mortar) as we find them," Leung stated on his Google Plus page.