Do you know if this law has ever been carried out? In the period since the Supreme Court interfered with the death penalty, I mean. My understanding is that the Supremes invalidated capital punishment for all but extreme cases of murder. "Ordinary" murders don't qualify.
The problem with capital punishment laws for rape and such crimes is that they would tend to result in a much lower number of convictions. And that, when dealing with adults, people do lie about whether the sex was consensual.
(Children lie too, but your're not supposed to be having sex with them at all, so consequensuality is irrelevant.)
Otherwise I'd be all for them.
The law's only a decade old. The USSC ruled rape isn't a capitol offense but only because it's considered unequal to punish rape with execution. However child rape being more heinous is so far ok per the USSC but there are challenges. There is at least one person in jail for it here. Florida has a similar law.