I do think there are some clinics out there that do basically lock up people to quit smoking. But I wouldn't put much stock in the technique. We lock up people all the time in our hospital and don't let people smoke. It's not in our smoking clinic; it's in our intensive care unit. You can lock people up for days and weeks if the condition is serious enough.
Technically, these people are detoxed from nicotine. Heck, some of them were comatose and never even experienced withdrawal. In theory, this sounds appealing to some smokers. But the reality of the situation is often, in fact maybe more often than not; the first thing these patients do upon release from the hospital is grab for a cigarette. You see these people never quit smoking. They were smokers who were just not allowed to smoke.
They don't learn anything about survival in the real world without smoking. They know how to be fed intravenously, they know how to use a remote on a television, but that is about it. The urge for a cigarette upon being released is incredible. It's interesting though, there is a real easy way to stop the urge. Throw them on a gurney, stick an IV in their arm and all of a sudden they don't need a cigarette. They are doing the one thing they learned, being a connected patient.
People need to face the real world as quickly as they can to start to break the associations of day to day rituals. Only then will they prove to themselves that there is life after smoking.
As far as being sad, this is normally experienced when quitting. Unlike the physical symptoms, striking hard and then dissipating within days, psychological symptoms are less predictable. But in some ways, they are also more controllable. I am going to attach to letters here to this post addressing these issues. They have been on the board recently, but so you don't have to scramble looking for them they will be right here.
Hope this helps a little.
P.S. There actually was a hospital in the Chicago area that used to have an inpatient unit for smoking cessation. It went under in less than a year of operation. I had three of their patient's come to my program to quit. Two of them made it. All of them said that they were basically doped up during the hospitalization. I think they were using a drug called clonidine at the time. Powerful antihypertensive that at one time was thought to be helpful. Never met anyone who actually got off smoking using it though. So if you find a program, check out what they do before assuming it's a good plan.