Usually charges like this don't stand on their own merit. So, for example, a person would probably not be charge for simply being out on my porch high. Suppose now that they were exchanged in a massive session on said patio, followed by loud music, well when the police show up after the neighbour calls than you can imagine this charge being applied.

The drunk driving situation you spoke about is not uncommon and it is applied pretty well across Canada. You are considered to be in control of a motor vehicle when you have the keys on your person and you've demonstrated some intent to be within the vehicle. We take drunk driving in Canada very seriously (and with good cause I think) and so when a person is found passed out drunk in their car, the law has been written as such as to default to it being a person who was in control of the vehicle. This stems from decades of people getting off of the hook for drunk driving merely because they passed out in their cars before being able to turn the key. I bet if you followed up with the person from the story the charges were dropped or he was able to get a lawyer who sorted it all out. I do not blame the police for enforcing the law as it is written and I do not slight the law in this instance for being cautious regarding drunk driving.