No problem with the principle, but its not practical. There are insufficient cells as it is. The construction costs etc alone would be prohibitive.
Think I suggested once before, a converted tanker/cargo ship anchored in the middle of the north sea might be useful. Chuck them on there and leave em to it. Never come off, just lob a few loaves at them occasionally. They can pray as much as they want then, or preach shite to each other or bum each other to death. Don't give a fuck. But once on, there's no press coverage or human rights lawyers crawling all over it.
Life means life, but with no quality of life.