Hamilton's Poisonous Parks

As a mum and a dog owner, the presence of poison heralded as DEADLY in the parks, gullies and walkways that we frequent is a cause for concern.    I have noticed that in many places the signage appears to be staying up indefinitely and  it's a right pain to not know if somewhere has or has not had poison laid. I wondered:  is this how this signage (and poisoning programme) is meant to work?