Making a kinect recognize the single player skeleton only

gistfile1.cs

/*Having made a kinect game as promotions for our company, we discovered that there was a problem in taking this game out into 
public and that was that if anyone stood behind the main player the game would just break in the sense
it wouldn't know how to track*/

//the code given by microsoft to activate the kinect tracking is as follows.

playerSkeleton = (from s in skeletonData
         where s.TrackingState == SkeletonTrackingState.Tracked
                 select s).FirstOrDefault();

//The problem here is that the kinect has its own way of stacking skeletons and deciding which one is 'First'. 

//The solution was to get it to attach to a certain ID at the start of the game and track only that from the start.

//Declare a variable called skeletonID and set it to -1 to indicate that no skeleton has been found

skeletonData = new Skeleton[skeletonFrame.SkeletonArrayLength];
                    skeletonFrame.CopySkeletonDataTo(this.skeletonData);
                    Skeleton playerSkeleton;
                    if (skeletonID == -1)
                    {
                        //this code is used if no skeleton has been detected
                        playerSkeleton = (from s in skeletonData
                                                   where s.TrackingState == SkeletonTrackingState.Tracked
                                                   select s).FirstOrDefault();
                        
                        
                    }
                    else
                    {
                        playerSkeleton = (from s in skeletonData
                                                   where s.TrackingState == SkeletonTrackingState.Tracked && s.TrackingId == skeletonID
                                                   select s).FirstOrDefault(); //once the skeleton has been detected we select only the one with the skeletonID stored (below)
                    }

                    if (playerSkeleton != null)
                    {
                        skeletonID = playerSkeleton.TrackingId; //if the skeleton gotten from the kinect isn't null then store that id. Yes this is being overwritten constantly. Maybe bad coding? I need to experiment and see what happens when I add a condition not to reset if it has already been set.
                        Joint rightHand = playerSkeleton.Joints[JointType.HandRight];
                        rightHandPosition = new Vector2((((0.5f * rightHand.Position.X) + 0.5f) * (1200)), (((-0.5f * rightHand.Position.Y) + 0.5f) * (900)));

                        Joint leftHand = playerSkeleton.Joints[JointType.HandLeft];
                        leftHandPosition = new Vector2((((0.5f * leftHand.Position.X) + 0.5f) * (1200)), (((-0.5f * leftHand.Position.Y) + 0.5f) * (900)));

                    }
                    else
                    {
                        skeletonID = -1; //if the skeleton is null (say when someone walks off the screen. Then the id used returns null. ) we reset the value in this line
                    }