Honesty is a trait of all us want to instill into our children. Hopefully we are a good example to our children. I know of people who lie about their kids ages to get their kids in cheaper. They lie on the phone about their husbands being home. Our kids hear this and will follow our example. Children with RAD have an especially hard time with lying. In fact, often, the only time they will look you in the eye is if they are lying. They lie about absurd things that cannot possibly be true and are completely shocked and amazed when mom knows it is not true. There are many reasons for this. One reason is that they believe all adults are stupid. Especially moms. They think we are easily fooled. Another is a need to control. There are several articles written about lying and how to handle it. Here are a few I have found.
http://www.attachment.org/pages_parents_articles10.php Nancy Thomas
http://www.deborahhage.com/articles/lying.html Deborah Hage
It is a tough battle and there are no easy answers. I think lying is a symptom of a deeper problem. While we must consequence the lying, as parents we also have to look beyond and work on why the need to lie is there. This is done through therapy, reading about RAD and time.