What precedents have been set?
There's no precedent for pre-emptivey restricting the freedoms of addicts/substance abusers/sick people any more. Like in the last half century. Even MH community has pretty much just given up, due to budget cuts, etc.
They don't incarcerate the alcoholic until he kills someone DWI. (And even then, probably not...)
They don't prosecute the person living with HIV/AIDS until he has been caught knowingly having unprotected sex and infecting someone.
They don't remove kids from home of a smoker...ever.
What about the severely mentally ill? They slip in and out of the system and rarely does anyone take note until they cause a disturbance or commit a crime.
This is sad but I think, sociealy, we have moved away from the concept of "the leper colony" and I don't see us going back any time soon.