When you make a new WCF project, sample service is generated for you. The default data contract is (I've just changed the string type field title):

[DataContract] public class CompositeType { bool boolValue = true; string name = "";

[DataMember]
public bool BoolValue
{
    get { return boolValue; }
    set { boolValue = value; }
}

[DataMember]
public string Name
{
    get { return name; }
    set { name = value; }
}

}

What is the point of having those private fields boolValue and name? Is it a good practice writing some data sanitizing or some other manipulations in contract, thus bloating it? It seems the only sane reason for me not writing to fields directly. So is it a bloatware or it has some reason behind it?