I am buying my first house and was able to meet the owners. They took me on a tour of the house and when they showed me the backyard they said the fence is before the property line. It's been like that since the house was built at the request of the 1st owner (they are the 2nd). I didn't think it was a problem to keep the fence as is but people are telling me this can be costly in the future. I really want this house but a fence that is about 4ft before it seems like a deal breaker. What problems can arise?