Why?
Who decides it's a terrorist?
Given that the vast majority of the NG is untrained and unversed in domestic law enforcement, what is "better" about this approach?
Several guys in my office are also currently reservists of some stripe, both officers and NCOs. If they change hats, is it cool if they use the EOD robot with a bomb on it?
Beyond that, people should be made aware of the fact that police forces are far better trained than the National Guard.