I like that idea.
What happens when they can't get by on what they make themselves, and start to go on "runs" outside their fence?
That’s what the landmines are for! ;)
That is not paradoxical. When Joe Arpaio created chain gangs for some of his prisoners, people assumed they were created as punishment. But the truth is that only trustees, who had earned the right through good behavior, are allowed to be on his chain gangs.
The reason is that jails are noisy and crowded and smelly. On a chain gang, you get fresh air and sunshine. Which is a surprisingly good motivator.
In any event, this is the same concept as one of these ex-con retirement towns. They are there only because they have earned the right, through good behavior, to be there. And if they make trouble, at the discretion of the town manager, they can be kicked out.
This is why, as I said before, that the fence is there, not to keep them in, but to keep other people out, unless they are formal visitors who are family or their representatives.
Otherwise, these are older people, with no motor vehicles, and many miles from anywhere else, likely a road, that they would have to hike to on foot. Which would be hard for someone young and strong.