An added Deterrent? One would think that was determined by a judge. I realize that society does level other deterrents but we have enough of them already. We don't need to be creating even more. That's just mean spirited and cruel.
The United States has the second highest prison population per capita in the world. Obviously our deterrents aren't enough. You are fed three squares a day, buy snacks if you have people on the outside contribute to your account, a field where you go outside in favorable weather and play sports, a little private room if your wife wants to come over to start a family, a pool room, a workout room, visitors, and working is an option. Need to get out of prison for a while? File a lawsuit against the state because you were served grape jelly instead of cherry. They will take you out for court battles and you can get out of there for a while.
We have the same thing in the outside world, but we call them get away weekends and we have to pay for them. For most good productive people, being confined anywhere is torture, but for people who don't do anything and waste their life anyway, it's not so bad.
A strong enough deterrent works every time it's tried, but we don't have strong deterrents here anymore, and no, watching cable television all day is not a deterrent. Watch the classic movie Cool Hand Luke sometime. If prisons were like that today, nobody would want to go there.