Poisoned dog treat notices.

[5.4MarkVIII]

OK, but the perpetrator is also the trespasser in your example - in this case the dog's owner (or parent for equivalency purposes) is responsible for picking up after their pet (this is a by-law as well which establishes precedent for the owner to be held responsible) which is not dissimilar for a parent to be responsible for their child. I'm drawing the equivalency by the perpetrator threatening the well-being/health of the dog and not the owner who is ultimately responsible (would be similar to threaten the child and not the parent).

I see the point there.
Either way hopefully it was just a bluff

[Ponyryd]

Personally I don't see anything wrong with it, at least there was a warning instead of just having poisoned the dog. Not sure what kind of inconsiderate moron doesn't clean up after their dog.