I agree, it is risky, in this example consent makes the difference between going to prison for the rest of your life or facing no consequences at all.

As we know, consent can be a fickle and hard to prove thing even when both parties are still alive to tell their story. If one of them is dead, then I don't think there's any way justice could ever be served.

I think in these instances, you get better outcomes erring on the side of a rule that just bans it altogether.