I also don't think that what the article describes is "gaming" the system, except maybe for the part about pretending to have not heard the questions before.

Generally, the reason I ask such questions of candidates is to make sure I'm dealing with someone who can actually analyze a problem and get a reasonable result. So if they nail the questions because they took time to study and get good at interview-style brain teasers, that's actually fine with me - it proves the person can execute a plan to get correct results.

I'm not sure I'd call anyone who successfully "games" the system incompetent.