This is expected evidence. Cryobiologists opposed to the practice have consistently labeled cryonics as flawed on grounds of dealing with frozen bodies, not due to cryoprotectant toxicity. They have failed to attack the strongest version of the argument, indicating that they either do not understand it (e.g. PZ Myers conflating E-VT with K-VT) or do not have sufficient doubt about vitrification to stake their reputation on it.
In a criminal case, the burden of proof is on the accuser, not the accused. Assisted suicide is quite illegal (and even considered a form of murder) in many jurisdictions. Therefore the question of whether someone in such a jurisdiction is guilty by legal standards should rest on whether the patient can be proven dead beyond a reasonable shadow of a doubt. I think this can easily be established for a straight-frozen person (due to severe structural damage to the cells), but not for a vitrified person.
You are free to support suicide / assisted dying, but this is a very different matter. The goal of cryonics is not to kill the patient or put an indefinite end to suffering, but to prolong life. That means that certain legal arguments against assisted suicide ("we do not want to make it okay to kill people on purpose") simply do not apply. Jurisdictions basing their laws against assisted suicide on those arguments may not be consistently opposed to cryonics.
beyond a reasonable shadow of a doubt
This seems to be a blend of two common expressions: "beyond a reasonable doubt" (which is used as an evidence standard in criminal law) and "a shadow of a doubt" (which is not).
Could you clarify what you mean here?
http://www.alcor.org/blog/?p=2716
Previously on LW: Aug 18, Aug 25, Aug 27, Jan 22.