But how can shareholders know? Let's say I bought some shares of VW before this scandal. Unless I'm an automotive engineer and have access to test equipment and

But how can shareholders know? Let's say I bought some shares of VW before this scandal. Unless I'm an automotive engineer and have access to test equipment and access to all models of the cars that have the fraudulent software on them, how can I possibly know that something unethical is going on? Even if I did meet all of those requirements, how would I be able to tell whether it was a bug vs. an intentional attempt to defraud the government? What if my government doesn't have those requirements? I don't see how it's even remotely possible for most shareholders to have this information.