Thank you for this. About a year ago I came across ShellCheck thanks to a comment just like this on Reddit. I also happened to be getting towards the end of a project which included hundreds of lines of shell scripts across dozens of files.
It turns out that despite my workplace having done quite a bit of shell scripting for previous projects, no one had heard about Shell Check. We had been using similar analysis tools for other languages but nothing for shell scripts. As you say, it turned up a huge number of errors, including some pretty spicy ones when we first started using it. It was genuinely surprising to see how many unique and terrible ways the scripts could have failed.
This is true but it also varies with industry. In defence and parts of the government, potential new hires are likely to receive a full and extensive background check, including academic records and past employment. It's similar for certain areas such as finance and some executive positions, either because it's considered fraud or dishonesty which is considered to make people unsuitable (e.g. in banking) or because the company is trying to manage risks and they want to be sure that they know what skeletons someone has in the closet.
This sort of thing wouldn't get you very far in those industries, and it's certainly not unheard of for people to be fired even after successfully getting the job. A surprisingly large number of people have been walked from high-paying finance jobs because they lied on their application, even months or years after being hired.