RE: Ethical/Legality?
You are wrong LAWFULLY if you trespass but not necessarily ETHICALLY in every circumstance. Again, focus on the end of that sentence - not in every circumstance. In most circumstances, yes, but not all. Believe it or not, the world is not black or white all of the time.
Sometimes people break laws they feel are unjust as in the case of civil disobedience. If I felt I'd have to break the law to retrieve an animal (I'd rightfully hunted on land that I had permission to hunt) by crossing a few yards over onto someone else's land that I knew would not grant me permission, then I'd do it - out of respect for the animal and because my intent was not to create this situation.
Not everyone can afford to buy land but everyone who is responsible should be allowed to hunt on public land or land where the landowner has granted permission. Not everyone lives in parts of the country with vast tracts of public or privateland available to hunting. Quite often, hunters on public or private land are forced to hunt near bordering property lines because of the sheer number of hunters sharing the property with them. Again, the world is not black and white. Try and think outside of your particular situation.