My last two Amazon purchases ended up being counterfit, even after spending a ton of time trying to avoid counterfits. I'm still going to use my fake electric toothbrush heads and fake Apple 5W USB charger, but I'm not using Amazon anymore.
But that then leads onto the whole fake component issue. For example the component will be a optocoupler but the dirt cheap knock off supply may not be using the same level of quality or a knock off component as those found in genuine power supplies which _could_ create a High to Low voltage path if that part failed.
Even a very cheap and simplified design can do that. I wouldn't say "a lot" at all, maybe a few percent of the cost at most. It's a corner that could possibly be cut, but it's not one of the bigger corners.
> Neither Sinar Harian nor its English-language peer the New Strait Times asserted that the youngster was electrocuted by the earphones he was wearing, but that was the conclusion reached by a number of international publications, including widely-read U.S.-based Vice and Teen Vogue, both of whom aggregated the story.
...
> As an emergency room doctor, Uren& stopped short of calling the notion impossible because “I have seen some strange things in my career thus far,” but he added the story that the teen died from being electrocuted by earbuds “strains credibility.”
[1] https://www.snopes.com/fact-check/electrocuted-by-earphones/
https://www.smh.com.au/business/consumer-affairs/store-which...