I don't know if I agree with the idea of staging an addiction intervention or not. A lot of people who become addicted to drugs or sex or food do it for some very deep psychological reasons. First of all, I'd be concerned about the wrong people participating in the addict intervention, like a sibling who sexually molested the addict or the friend who first introduced him or her to their drug of choice. I'd want to make sure the intervention specialist was aware of all the dynamics before letting people into that meeting.
I'd also be concerned about the addict's future recovery if the intervention went wrong. I understand people may have the best intentions, but someone with a heroin or cocaine addiction is still an adult. He or she has every legal right not to seek treatment for their personal problems. A successful intervention might get them to agree to enter an addiction center, but an unsuccessful one might send them deeper into their disease. I think everyone involved in a drug addiction intervention needs to understand the risks as well as the rewards.