Botom line is the land is posted and if you violate the landowners rights, you are trespassing.
If you trespass you are breaking the law.
If you break the law you are not ethical.
If you don't want the possibiltyof thathappening, hunt elsewhere.
Ain't no grey area here.
Pretty simple if you ask me. Avoid a situation like that to begin with and you wouldn't have to worry about an "ethical" decision. It sounds like it is known that the neighbor is a jerk and that's too bad. However, knowing this to begin with and hunting near such land, you are flirting with a bad situation. Either way you cut it even if the guy is a jackass he does have the same rights as a landowner as hunters do. I've given up nice pieces of hunting land before for the same exact reason.