People who grab ones ancestor in the wrong tree are usually just clickophiles anyway and probably will never pay attention to your messages and really don't care. They probably never even think about it because they are so proud to have X amount of names in their trees. I would send messages every once in a while to remind them but other than that, there is not anything you can do. My gg grand father had a very common name-James Johnson-and there are several trees with him included which are completely wrong. I have sent messages to the tree owners telling them that he must have been a miracle man because he was living in two different states at the same time in 1850 with two different families. It's just an exercise in futility. Once in a while you might get a reply and a person will correct their error and thank me for giving them the right information. I guess you could say that is my reward.