Not sure whether it counts as a plaque! It's more a sign.
Its headed with a Royal Cypher [Can't work out whos]
'Notice. Section (45) (1)All persons ordered into quarantine and for that purpose may be detained on board the vessel or in a quarantine station until released in accordance with this act or the regulations and while so detained shall be subject to the regulations regulating the performance of quarantine and the government of...
Quarantine Station (2) No person ordered into quarantine shall commit any breach of the regulations regulating the performance of a quarantine station
PENALTY TWO HUNDRED DOLLARS $200