I have never asked anyone to actually try the controlled drinking - but my sponsor said it was the only option for one guy he was working with- and it wasn't going to be the sponsee that dictated how much to drink...
Goes like this: What is your favorite drink? (Ice cold vodka from the freezer, let's say).
For a period of time, I will call you each day and tell you how much to drink - that is how much you are going to have.
So Monday - say, you can have 2 of your favorite drinks
Tuesday you can have 1
Wednesday you can have 3
Thursday you can't have a drink
Friday you can't have a drink
Saturday you can have four
Sunday you can't have any
The thing is - you never know in advance how much you are going to be 'allowed' to drink on any given day, I wouldn't even call at the same time each day to let you know, maybe I won't call at all to let you know. Say this goes on for 30 days.....how would you react?
I know what would happen to me - one of those times I would just say 'F it' and get drunk. The thought of someone calling me, telling me how much alcohol I could have on a given day was crazy - I didn't have to do the 'experiment' myself...my experience was clear that I could not control my drinking, let alone let someone else control it for me.
I think the point of it all is to see if that physical reaction in the form of a craving develops. In AA - the physical part of alcoholism is that alcohol reacts differently on the body of people affected. We (I) have an allergic reaction to alcohol that manifests itself as a craving for more alcohol - once that craving is active, there is no way to not drink if alcohol is available, mental faculties are useless. (This is outlined in the Doctor's Opinion and More About Alcoholism).
Most can do this 'test' mentally...but I have heard of it actually being done. If the person is not alcoholic - it won't be a big deal. If they are - they will drink more than rationed.
Simple.