I don't think they will have any contractual issues. All they will be calling DirecTV for is activating the receivers. The contract would come into play if they were getting new equipment and/or and installation, I believe.
As for the old receivers, I don't think that will be an issue. I have recently had my original receiver from early '98 activated. My FIL is using his original from late '96 or early '97 still.
As for the old receivers, I don't think that will be an issue. I have recently had my original receiver from early '98 activated. My FIL is using his original from late '96 or early '97 still.