If I have to discipline my children, I also teach them that they must try hard to get back to good. Just because they sat in their room for a few days doesn't mean I automatically begin trusting them again. They need to show me that they will not repeat the behavior that got them in trouble in the first place. They damaged my trust in them. Obviously they can't repair it by sitting in their bedrooms. But they also haven't shown me why I should trust them again. So where as curfew might have been 11 before, now it might be 9 until they can show me that they can be home on time consistently. Where as they were trusted to drive to and from school by themselves before, now I take them and pick them up until they can demonstrate to me that they won't ditch anymore. And so on.
This just isn't a situation where we watch the clock, and then at the right time we boot them out the door and say, "There you go Mr. Child Molester. Enjoy your job at the day care center!"
There is a huge difference between a child and an adult. A child is still being taught, while an adult, for better or worse, is presumed to have been taught.
Besides, what else can society do? You dismiss my argument by calling it a "revolving door" policy of criminal justice which I think ignores the point I was making. The point is, when a person breaks the law, that person gets punished according to the law. How many criminals have we heard of who got released for "good behavior" while in prison and went on committing more crimes? So what good does it do to try and figure out if these hundreds of thousands of criminals are really worthy of being released; if they've learned their lesson and deserve to be blessed with freedom again?
To use your example, your child CANNOT prove to you he will not climb over the neighbor's fence again while sitting in his room being punished. The only way you can trust him again, is by allowing him to go and play in the back yard again, right next to the fence. Or rather, you make up your mind that your child is worthy of being trusted again and let him play in the back yard. Or do you tell your son that he's grounded for two days, then sometime on the first day, you decide he really isn't sorry for climbing over the fence and ground him for another seven days?
Or perhaps you are the kind of parent who says, "you're grounded until I feel you really mean it when you say you're sorry!" I would imagine that he'd learn really really quickly how to lie to your face to get out of being punished and why? Because YOU now are not trustworthy. "This is the crime -- this is the punishment. But not really, because I can decide you don't mean it and keep you longer."
I have a great deal of trust in my children; one thing is that they know that I will punish, and that I do what I say I will do. They can trust me to ALSO listen to them, weigh outcomes and decide what's in their best interests because I'm still teaching them to learn and understand right from wrong. I tell my kids what I expect and usually what the punishment will be if they break a rule. My kids are good kids -- I rarely have to punish them anyway, so I'm lucky in that regard.
But as to adults, that's a different story. Harsher and harsher penalties, IMO, do not change the structure of criminals and society. Getting adequate mental health care back again, punishments that actually fit the crime, giving judges back more leeway and getting rid of mandatory minimums and so on, mentoring programs (through neighbors and volunteers -- certainly not through the .gov), less emphasis on college and more emphasis on technical schools/trade schools and apprenticeships... lots of things that should be done besides longer and longer prison sentences. I just shudder to think that the prison system in the US is the fastest growing "industry."
But, I'm firmly on the side that once you're out of jail, all of your civil rights should be restored. If you're on house arrest or on probation, same difference as prison -- no rights.