I did end up meeting the neighbor...and apologizing to him. He was very cool about it and didn't seem to be upset with me about the situation. I told him that I never would have put my stand there if the other guy hadn't told me that it was 100% ok. He was very understanding.

As far as lending a gun goes, I felt that since I was going to be there and I had an extra gun, it was the friendly thing to do.

In the end, I have to chalk this up to a lesson learned. My real friends are the best friends that I have ever had, and they understood completely about why I hunted with this other idiot. The offer to hunt that much land with so little pressure was a good offer, until it changed a week before hunting season. The lesson I learned from this? If it seems to good to be true, it probably is.