Sadly, it's almost certainly against municipal code.
All it takes is one jerk to make a smart street team effort go bad by complaining to the police or mayor.
All one has to do is discard it. To go the extra mile to trudge down to the police station or Mayor's office and make a stink about it appearing to be a ticket would indeed make the person a vindictive jerk.
Now, as an aside, the mindset of one who sees a "ticket" on their car from a distance is probably not conducive to a positive response to the pitch.
The fact that the poster here clearly calculated the weight of his actions versus the impact of the preceding event the on the attendee was what I thought was interesting.
It's a calculated risk, and one or two pings of interest is clearly worth the possible fine.
Again, in my opinion.