Yes, it is very good to collect the KYC from the bounty participants in order to eliminate multiple accounts and as well as a company should maintain documents if they face problems with the government. Whether they are doing the business in a legit way or not.
say bounty hunters, Reg on web site. and you can check all IP. and if some people use one IP you can delete all of them. + if 1 acc have 100-200 IP - its mean = IP changer, and you can delete to
KYC is last chance.