EDIT:
It appears hunters have the option to sell their bounty stakes for ETH on an exchange. Those who bought those stakes will have to undergo KYC also before they can convert the stakes into tokens.
I don't know it exactly, I would guess that's only possible if you receive the bounty stakes in your wallet. And for doing so, you need to pass KYC. I can ask a participant if you want, I had a few PMs but he's afraid to create a flagg because he fears that the team will disqualify him.
They partnered with this exchange called Tokpie where hunters can trade their weekly/monthly stakes for eth while the bounty is ongoing. That's one option they can do to avoid KYC and still be rewarded (in eth). Those who bought the stakes can then convert it to TGN upon distribution. Anyway, their admin (terragreen) said those buyers aren't required to undergo KYC.