Sorry, I don't see the connection. Yes, a successful candidate is worth a lot of money to Kalzumeus, and they are incented to make sure that the solutions are real and not plagiarized. But that salary is worth even more to that successful candidate, and hence they would be willing to pay handsomely for someone to write customized, non-plagiarized solutions for them if it gets them in. (The mythical level 45 mentioned would cost $44K. If I'd done the math, I probably would've made it more. I guess the level 52 would be nearly $750K...)

For now, I'm assuming they have good protection against automated solutions. If it were just a matter of detecting plagiarism, you're right that it would be trivial. (Heck, I even cofounded a company that did code plagiarism detection, so I have a very good sense for how easy or hard it is. tl;dr: it's straightforward to defeat a plagiarism detector if you are sufficiently motivated and knowledgeable and willing to put in some time to go through all the code, but people/companies who plagiarize are typically none of those.)

Detecting whether someone else is doing the candidate's work, on the other hand, is impossible. Unless you bend the rules. Fortunately, the rules seem pretty pliable to me -- when a candidate arrives at a company's interview, spot-check them on their understanding of a few of "their" trickier solutions. It's a logistical nuisance, to be sure.

"when a candidate arrives at a company's interview, spot-check them on their understanding of a few of "their" trickier solutions."

The verification burden shouldn't be on the hiring company, it should be Kalzumeus...

Sure, but if Kalzumeus can't verify the candidate's identity while playing the game, how could they verify it afterwards? Until someone physically walks through your door, you really have no guaranteed way of knowing who you're talking to.

I don't think they'll really need to worry about these things for quite a while, though. Good problems to have, I guess.

They won't look closely. As you seem to see yourself, they would rather spend $50k per engineer to a 3rd party service than perform proper recruiting by themselves in house.

You seem to be trolling, but to clarify I was suggesting Starfighter would be looking closely before referring candidates to clients. Their reputation depends on the quality of the candidates they refer.

I'm not sure why you're being downvoted. Obviously, if they reference Danny the Word programmer as a ninja rockstar to a Fortune 500 on a regular basis, their business is going to take a nosedive.