When your personal property is in public right of way you can certainly touch it.
Wouldn't that imply that walking down a sidewalk (a public right of way) any police officer could stop me for no reason and cavity search me from head to toe in anticipation that he might find something illegal?
Chalking tires anticipates a crime not yet committed, there's really no two ways about the intent of marking somebody's tires ... the question is really more about whether (conceptually) the act of marking someones tires is an imposition on their private property, one taken without a warrant, or whether it is simply illegal from the perspective that it violates some basic rights established by Charter or Constitution.
But you're right ... for those times when it's found to be in violation of the 4th Amendment, it's gone to another court and found to be no such violation.
But obviously the discrepancy between the two courts indicates that it remains a grey area, and one that's not fully explored or understood from a legal perspective.