That's a great example too, because Amazon actually ended up following up and banning cables that were found to be non-compliant with the spec, largely based on his reviews: http://lifehacker.com/amazon-bans-non-compliant-usb-c-cables...
Having Amazon test every cable obviously doesn't scale either but couldn't they require the vendors to provide test results showing that the cable is spec compliant? Of course the vendor could forge the results, but that's intentionally malicious and this would at least catch non-malicious accidents.
Electricity goes through it. Check. UL listed? Check. Okay, goes on the suggestions page.