I agree on this. KYC should be announced before the program start so as to give a heads up to participants that it will be implementing one. Also, this is in consideration of the security risks involved for the participants who will give out their KYC information which is usually confidential in nature.
Yes, as much as the investment is risky, KYC is also very risky thinking that you give your personal informations and that makes it risky though is the programs security but how about our security so it is good thing to announced before the program so people will not surprised at the end of the bounty.