I think under the circumstances it may actually put a smile on peoples faces. They are probably already in a good mood and the right mindset for something like this.

This was a relatively common tactic in Chicago a few years ago, done by restaurants and a band if I remember correctly. Heading to your car on your way to work in the morning and finding a fake ticket that ended up being, as you say, junk mail, really made people angry. I am pretty sure the city got involved people were so mad.