My opinion, based on my experience, see the use of a game decoy in the attempt to catch a subject engaging in unlawful conduct is neither enticement nor entrapment.
If one is predisposed to violate fish and game laws, or any laws.....the mere presence of that decoy isn't creating the situation for them that they haven't already done or considered doing.....internet crimes against children chatrooms, controlled buy/bust for narcotics, murder for hire, anti-prostitution operations, etc....the lists go on, come to mind as legitimate law enforcement activities similar to placing a game decoy out.
While some may say/feel that poaching, over harvest, etc are not on the same "level" as these crimes....my argument would be that to an officer entrusted with enforcing fish and game laws they are. Especially considering that not catching one in the act of a poaching violation extremely limits the ability to establish probable cause for an arrest or a search warrant application. Being in the right place at the right time to catch a poacher is called luck. Creating the time and place to put the poacher on your playing field is called routine work.
Additionally, to us outdoors persons, we see the attacks on what we enjoy as a pastime by private interest groups and political agendas monthly, and behavior of those who CHOOSE to engage in unlawful activity hurt us all.