This is a good question... If you see it as punishment of an evil person, it follows that they should be denied cryonics for the same reason they are being killed.
I would not necessarily say it follows. Sentencing someone to information death is a whole different level of punishment than sentencing them to execution. In most cases even historically the soon to be executed criminals are allowed to see a priest. This suggest that the intended punishment is not usually eternal in nature.
Sure, but cryonics isn't religious, it's medical. Like doing CPR on the patient. And information death is what happens with the current death penalty. Taking away information death would be changing the punishment's essential nature.
If someone is sentenced to life in prison or the death penalty, should they also be prohibited from signing up for cryonics? Specifically, I'm referring to people like these: http://en.wikipedia.org/wiki/List_of_United_States_death_row_inmates
I am not talking about providing it for them, just allowing them to sign up for it provided they can somehow get enough money together and allowing a response team into the prison to retrieve the body after the prisoner has died or been executed by lethal injection. I think they should be allowed access to cryonics, because we don't know enough yet about the brain to determine how much of their criminal behavior is due to mental illness/disorder and how much is due to free will. It may be possible to diagnose and cure people like Jeffrey Dahmer in the future before they commit any crimes, or to cure those already in prison such that they won't commit any more crimes.
As cryonics gets more and more popular, this will become an issue, especially when the first death row inmate wants to sign up for it.