Can you copy your CAC?

This question goes out to the JAG members are there any surcomstainces that would permit you to copy your CAC? One example would be for your military unit. I was reading through some post and seen one that talked about it. I have always gone off the rule to never do it and it has served me well and will continue to use it until told other wise. Then I was reading the post and it got me thinking about the fact that I don't know the jrule very well and could be more helpful to learn more about it. Please leave your comments.