It depends on what you mean by “diversion”. It's hard to sell the cannabis you're going to get from four one-metre plants. You're not going to get that much, but certainly, sharing it with your friends, I think that'll happen.
If you really want to stop people from diverting cannabis, make it cheap. The only reason that people grow and sell cannabis is that it's very expensive and very profitable when this plant is worth $5 to $10 a gram. It doesn't matter if it's legal or not. If I can grow a plant in my home that's worth $1,000 and then sell it.... People are going to do that.
The way to stop diversion and to get people to not be doing that is simply to make cannabis much more affordable, to make the price lower, to where it should be for a natural product. It's the only plant we sell by the gram, and not by the pound, so I would like to see cannabis at $1 a gram or something like that. It's still an incredibly high price for a little bit of plant matter, but if there's no profit in it, that would eliminate the vast majority of diversion. If legal cannabis maintains the same price structure as illegal cannabis, then the illegal market will continue. That's just how it's going to be because of the profitability. That's the real question.
I think most people growing four plants at home are going to grow it for themselves or to share with their friends and family. They're not going to be selling it, because the profit margin isn't that great for just a few plants. You're going to want to have a bigger grow to really satisfy the underground market. I think that's where most of the underground market will remain.