[andrewclunn]

Simplest approach is to make two categories blended and pure. With contestants only being allowed to enter one. This would incentivize otherwise would be cheaters yo enter the category they can legit compete in, reducing the amount pf testing required to only those in the pure category, which would keep costs down.

[cbzbc]

Not really; there'd still be a premium for the "pure" category and so incentive for people to continue to cheat.