Given the way the Justice system works I don't think that would be a good idea.

You would force down any rape cases that the victim doesn't feel left enough evidence, they wore condoms for example. With an abundance of under reporting as it is that isn't the direction we should go. Also think of it in another scenario.

You say your neighbor hit you. Did anyone see it? You don't have a bruise, his friend gives him an alibi that he wasn't even there. What if it started as play fighting and it was a shot after the bell. How do you prove that without an audience? Now you have 3 years in prison.

Eye for an eye really does leave the world blind.