Is there something the Standard Model doesn't want us to know?

Currently there does not exist an accepted way to nonperturbatively regulate chiral gauge theories, such as the Standard Model. A lattice formulation leads to mirror fermions that we do not see, and decoupling via a big mass would break the gauge symmetry. Past approaches for eliminating the mirror fermions include (i) breaking the gauge symmetry, (ii) endowing them with an exotic strong interaction in hopes that it induces a mass gap. I explore an alternative where the mirror fermions decouple from the visible world via soft form factors. An interesting feature of the mechanism is that the gauge field topology remains sensitive to their existence. Could these exotic fermions exist in Nature?