I just remembered a conversation I had during my weekend round that threw up a potentially daft question but here goes. Our course neighbours another course, so if you go over the boundary it's out of bounds. But what if someone on the neighbouring course threw it back over the hedge so it landed in play? Do you take this wonderful gift and continue to play your second shot? My guess is if you found the ball there incidentally, i.e. you had no idea how it stayed in bounds but assume it hit a tree or something, you would obviously play it; but if you visibly saw it come flying over the hedge like 30 seconds after you hit it then that's not allowed. But I really don't know? This must have happened at some point in history.