^But, were Khan and his people criminals? Again, I point to their lack of choice over their actions, based on being unwilling victims of genetic manipulation. And, if Kirk and co. don't "press charges", as it were, then that would leave Khan and friends lose in the Federation, or locked up for being who they are, since there is an apparent Federation wide fear of genetic alteration, as shown in DS9 re Bashir, and in the ENT eps dealing with the "supermen". So, I say Kirk knew that he was not going to persue charges, and rather then condemn Khan and company to some cage somewhere, decided to give them the opportunity to live out their lives challenged, but free. The humane thing to do, no?