Kidney donation a condition of release?

This news story appears to me to raise ethical questions.

http://www.cnn.com/2010/CRIME/12/30/mississippi.sisters.prison.release/index.html?hpt=Sbin

Apparently, two sisters in Mississippi received life sentences for an armed robbery that netted $11. Having each served 16 years in prison they are now each consider rehabilitated and no longer a threat to society. One sister's dialysis treatments three times per week is costing the state $190,000 a year. Governor Barbour's decision is apparently being well-received by all.

But ethically, an organ donation must be voluntary. Not even a court of law can require a person to become an organ donor even if a specific death will result for lack of a suitable organ. If this were a research proposal being considered by an Institutional Review Board (IRB) I think the IRB reviewers would be hard pressed to believe this is not a coerced consent. The state has apparently concluded that the sisters should not be in prison. Assuming the sister receiving dialysis will be eligible for Medicaid upon release, it is in the financial interest of the state for her to receive an organ transplant. From an ethical perspective, it seems to me that the better sequence of events would be to immediately release the two women and then ask the potential donor if she wants to make the organ donation. Is it possible that the prospective donor has refused to make the donation unless both sisters are first released from prison? If this is the case, does this amount to selling one's organ, which may be a violation of law?

Does this news story suggest that in the future a convicted criminal's "debt to society" might be paid by "voluntary" organ donations (to unknown others) in Mississippi? It seems to me that the state has a conflict of interest regarding the medical care of the sister needing dialysis and that making release contingent upon the organ donation may not be ethical or wise.