No it isn't, their strategy is great at increasing the rate at which they select those deadly "bad hires". There's just an insane amount of risk in doing these sorts of tech interview things; code up a quick monte carlo simulation to convince yourself if you like. It's just that the risk doesn't fall on the improperly aligned humans conducting the interview, it's offloaded onto the company.
Exactly, you could just as easily hire a bad candidate because they got lucky, and this happens all the time.