It does not sound practical.
1) They would have to be frozen immediately after life had been extinguished in them - so they are, in effect, dead. So they have had the death sentence, which would then have to be be reversed when/if the researchers have got the technique beyond freezing sperm/ova/embryo.
2) Good quality embryos are frozen after two or five days of development At 2 days they consist of 2 cells, by 5 days there are about 100 cells with a fluid- filled space Watch the first few days An adult human being has about 100 trillion cells, each made mostly of water. If you have frozen a liquid, you know how water expands when frozen to distort the container. Cell walls are burst by the pressure. Even with so small a thing as an embryo, many do not survive the thawing process,
Freezing a complete human is many many times more complicated than freezing less that a hundred embryonic cells - which have not yet differentiated. Freezing an adult and thawing them out successfully is not going to happen in the immediate future.
3) How long would they be in stasis? Who knows. Who would be employed to maintain the freezers for possibly hundreds of years? Would they be motivated to ensure that these detested individuals were preserved intact? What would the cost be of hundreds of years of supplying power to the freezers and paying the guards/technicians? On top of the cost of the freezing and the thawing.
4) If they survived being frozen and thawed, what then. They would be released into an alien world they were not prepared for. How would money work in the distant future? With no employment prospects, how would the ex-prisoners live? Their previous jobs would no longer exist, they would not have skills for the New World Order (would a Tudor peasant be equipped for life in a big 21st century city? Only by begging or crime.) Would they have to be supported on whatever the equivalent will be of benefits?
No, not on.