The model they proposed is just one sort of drug user group. Existing models span the anonymity of Narcotics Anonymous to the activism of Dutch drug users' 'unions'. Each of the models poses some serious problems for potential members. To stand any chance of success, a user organisation will probably need to incorporate aspects from several of the models in the panel. But perhaps the biggest problem is mobilising support among active drug users.
Drug use is illegal, and drug users are highly stigmatised.
Those most likely to have the skills needed by a user group are also the ones most likely to be employed. They have a lot to lose if they are fingered as active users - even if they are stabilised on methadone. I can personally assure you that no matter how stable you are, or how useful your activism is, once you are 'outed' you will experience serious discrimination that can be very difficult to overcome. What this means is that often those most willing to get involved also lack the kind of skills a drug user organisation needs. The second problem is that of how representative the group can be, and how it makes its decisions.