You aren't being dirty, you're hunting the situation. If he had oaks and the deer trail lead by your stand to his oaks, you'd hunt that trail. You can take advantage of the cornpile, or you can make the deer move to your food plots. It isn't like you're leaving an old t-shirt in the cornpile. Remember, if he'd wanted to respect your hunting area the cornpile would be in the middle of his property. His objective is to draw the deer from your hunting property to his. There's nothing wrong with fighting fire with fire, as long as you do it politely with a smile on your face.

Also, if you've never hunted a cornpile, it isn't what it's made out to be. Some think you just walk out and shoot a deer whenever you want to and that isn't the case. Deer catch on fast at a cornpile, at least they do around here. By the way, I put a feeder out after a few weeks and everything cleared out. It seems like the deer are scared to death of it.