If I were one of your members and you asked me whether I thought counterfeiting was going to be a problem, I might say yes. I don't know, and I haven't necessarily examined all the evidence or looked at the studies.
It seems to me the validity of your process is in question. I'm wondering why you think in particular that plain packaging will lead to more counterfeiting, given that legal products will have a difficult-to-counterfeit tax stamp?