Can you score points in a single-pet exhibition if you have no pets, but you either have the Whip of Obedience, or you have chosen the Volunteering for Judging action?

If you have no pets, you cannot participate a single-pet exhibition, regardless of bonuses (Whip of Obedience, Judging action), as you are unable to send a pet to that exhibition. You can compete in full-display exhibitions with these bonuses, though, even if you have no pet.