Yeah, I feel they are barking up the wrong tree. If you look at the numbers, there's not much revenue once N is much above 100. I think there's potential for some use of the work, but you still need a benefactor.

Hi, great post. I've also noted the square-root rule and think it should be more widely known. I've also co-authored a paper showing that the dominant assurance contract described by Tabarrok does not lead to larger profit than a standard contract with the same parameters and have some other work that I'm writing up on the same thing for large N with fixed and variable payments. 

I've come up with the upper limit of $\frac{\mu +\sigma \sqrt{2}}{sqrt2\pi (N-1)K_N}$ for the fixed-payment, and something similar for variable payment.

Is there a lot of interest in this at the moment? I agree, it's of narrow interest, so I'm curious into why you've posted this now.

(In case you're wondering how I got here, I followed Tabarrok's recent post about EnsureDone on MarginalRevolution. I'd heard of LessWrong before then but hadn't joined).