Case law is based upon court decisions in a specific location, for example in a certain town west of Toronto it is legal to get head in a car in public because a judge one day said it was a normal part of growing up and went along with necking etc..... this means that the crown attornies in that area will not bother to bring this to court anymore as a good defence lawyer will bring this particular case up and will lead his client to an aquital. However 10 km down the road they are still going to the back of the highschool and arresting teenagers for indecent acts for the same thing..... It's screwed.

The Narcotic laws in Canada are very complex and are not understood by anybody so if you can figure them out let me know cause I still got friends looking to hire you!
The green zone is just a case of heads getting some instead of getting head.....
I hope this helps.

peace (pipe)