Well, I would use alcohol as an example of how unsatisfactory regulation has been under a legal status. Young people use alcohol much more than one would like to see, yet it is a legal drug. It's simply the case that older people above the legal age for purchasing share it with the younger people. That is even easier to do with cannabis, because it's rather hard to hide a bottle of liquor when you leave the LCBO. It would not be difficult at all to hide a small package of cannabis in your pocket.
The point, therefore, is that the two, both alcohol and cannabis, produce problems. We have used different measures to control them for traditional and historical cultural reasons. The question is, do we wish to repeat the same mistakes with cannabis that we have made with alcohol in not training young people to realize that there are safe limits to what use permits? So far, our record with alcohol does not make us very optimistic about how to achieve that with cannabis.
I think that's why I say it is necessary to be very cautious about changes in policy that may increase the use and make it more difficult still to control, within healthy levels, the extent of use.