Postering generally will not amount to criminal mischief

R. v. Jeffers, 2012 ONCA 1 deals with a very sad case (it is worth a read for the counselling murder charges).  That said, the decision is a good source for the principle that postering will not, in general, amount to criminal mischief:

[19]         The trial judge erred in her appreciation of the meaning of "damage" under the mischief provisions of the Code.  To criminalize mischief, the damage must be more than negligible, more than a minor inconvenience.  To prove damage the Crown must show that the usefulness or value of the property has been impaired, at least temporarily.  Proulx J.A. set out the test in R. v. Quickfall (1993), 78 C.C.C. (3d) 563, at p. 566 (Q.C.A.):

Without disagreeing with this definition of the word "damage" according to which the thing is "rendered less suited for its intended purpose", I would add, on the basis of my reading of the dictionaries, that "damages" means that at least temporarily, the usefulness or the value of the property is impaired, whether or not the property was harmed or ruined.  In this sense and, with respect for the contrary opinion, I do not believe that "the least bit of damage" is sufficient to constitute mischief. [Emphasis in original.] [Footnotes omitted.]

[20]         In the present case, none of Mr. Jeffers' posters interfered with the utility of the signs, poles or parking meters, or impaired their value.  All of the city's property remained functional.  At most, the glue affixed to the posters made them somewhat difficult to remove.  This minor difficulty does not amount to damage under s. 430(a) of the Code.

[21]         The test for damage amounting to criminal mischief reflects an appropriate balance between individual and societal rights.  Individuals have long used postering as an effective and inexpensive means of communicative expression – whether to give notice of a lost pet, an upcoming local concert, or a person's availability to do home repairs.  Criminalizing this kind of conduct is not in society's interest. 

[22]         On the other hand, local municipalities have a legitimate interest in ensuring that posters do not become a nuisance or impair the safe operation of their signs, poles and meters.  For this reason, the regulation of postering on public property – be it the size, appearance or location of the poster – is best left to local by-law legislation: see Peterborough Corp. v. Ramsden, [1993] 2 S.C.R. 1084.