Not illegal. Property owners have an action in trespass at their disposal, should they pursue it. It is not illegal per se to trespass. Learn your local laws before you shoot.
People hunt in and around my property, and I have no problem so long as they respect the safety zones and hunt safely. So I don't care, maybe I'm the minority here.
Not unethical. I can shoot into my neighbor's ground without a second thought, as I am a permittee. I think of myself as a pretty ethical guy.
What in the blazes are you talking about?[&:]
It IS illegal here! It IS unethical anywhere! Are you saying you shoot deer on your neighbors land from your land without permission? That is what we're talking about. If you do I'd suggest reevaluating your ethics.