The celebrants on April 20 don't necessarily know the history of how cannabis came to be illegal, but they do know cannabis is less harmful to users than all other illicit drugs and considerably less harmful than alcohol and tobacco. They know that the greatest threat from cannabis lies in its continued illegality by policy makers who wish the evidence would just go away.
Instead of being laughed off as a silly mistake, this deserves serious scrutiny. Where there is one mistake caught only by a fluke, there are probably many more that didn't get noticed. Harper's cannabis crackdown means that our courts are steadily processing more and more small-time cannabis cases. As these cases clog the system, judges will find themselves even more pressed to deal with them quickly, and be paying even less attention to the specific details in each case. These kinds of sentencing mistakes will only happen more often.