The box these bearings came in has one of the main signs that they are cheap counterfeit parts. Specifically, it does not have the name of a known reputable bearing manufacturer on it. (No-one but a large, competent bearing manufacturer has the capability to make rolling element bearings of acceptable quality. It cannot be done in some cottage industry in China.) You should never, ever, buy anything like that. But likely if you bought them on line or by phone or mail you would have no way of knowing, so you have no choice.
The blame does lie entirely with the supplier, who must know that the parts they are supplying are bogus. They have not used due diligence, and most likely could face criminal charges, all the way up to corporate manslaughter, if one of their products caused an accident. I get the impression that some parts suppliers are managed by complete idiots, who are neither capable of behaving responsibly not understanding the possible consequences for them if they do not. As long as they make their fat profit, of course.
I would strongly recommend reporting this to Trading Standards, who have the power to investigate the supply chain and prosecute whoever committed the fraud, because fraud it is.
It is easy for me to say this because I work in an industry where we are all trained to spot bogus parts, but how is the average person supposed to know? And if in my two most recent jobs (aircraft and nuclear), we were finding that we were getting counterfeit parts through carefully managed supply chains, how is the average person going to avoid such stuff? I personally have seen a batch of electronic components which were not what they seemed to be, and nearly got into a nuclear control system. It makes me sick, this whole business of counterfeit parts. It is recognised in the aircraft industry that sooner or later a jumbo jet will crash because of a bogus part, despite all the checks which the maintenance companies apply. A serious disaster like that might just make the scumbag politicians who know about this and tolerate it finally take action against China, the root of the problem. Meanwhile, we have no way of knowing just how many high tensile bolts, holding important things together, are actually mild steel.....
