That this involved lying to your employers. There is no social expectation that you only work one job, plenty of people work multiple jobs, but there is a social expectation that you do what you said you'd do, and it turns out you have a bit of a mathematical problem if you try to work 4 eight hour jobs in a 24 hour day.
Which is, as per the article, how he was caught. Turns out if you call in sick at one place and then push code to github for your other jobs most employers aren't paying you for that.