Came across an informative document from the City of Toronto Revenue Services regarding parking ticket activity for the year 2008:

It's a high-level overview used by the city for whatever reason.

The most intriguing part I noticed was on page 3 in Table 2. This table provides a breakdown of tickets cancelled and the general reasons for the cancellation. The second reason for cancellation was as follows:

"Drove Away – offender drives away before officer can serve the tag."

I was under the impression that once parking enforcement entered your plate number on the ticket (or machine that prints the ticket), it really was irrelevant whether they placed the ticket on your car or not since you will have to receive a "notice of impending conviction form" anyway which becomes the "serving" of the ticket.

Failure to respond

18. (1) The person designated by the regulations may give the defendant a notice of impending conviction if,

(a) at least fifteen days and no more than thirty-five days have elapsed since the alleged infraction occurred;

(b) the defendant has not paid the fine; and

(c) a notice of intention to appear has not been received. 1992, c. 20, s. 1 (1); 1993, c. 31, s. 1 (10).

No response to impending conviction notice

18.2 (1) A defendant who has been given a notice of impending conviction shall be deemed not to dispute the charge if fifteen days have elapsed since the defendant was given the notice, the fine has not been paid and a notice of intention to appear has not been received.

Hence, I am curious as to why the city would cancel these tickets in the first place since the POA covers the failure to initially serve anyway (not that I'm complaining but it seems strange to me at least).

Thoughts?

If you do not pay your ticket, you are deemed to be in disagreement with it. If you drove away instead of receiving it would be one way of it. The court has to go through all the unpaid tickets, and review them. If there is a flag that you drive away/weren't served, that might cancel the ticket for you.