Well, as you have pointed out (I mean: http://lesswrong.com/lw/e4e/an_angle_of_attack_on_open_problem_1/7862 ) , we are probably already dealing with non-real-line utilities. So we could just lose one hold point per hold.

Also, we could require Quirrell to present each source code string infinitely many times.

This would remove stalemates of Quirrell not offering some string at all, and would give us some incentive to accept a many programs as we can verify.