I say we should think of implementing a new project on that server feature. As couple of people stated above, new players don't get the meaning of this and I wouldn't count as exception the regular ones. As I daily notice, these two occupations are not getting used at all, because they don't have any important purpose.
What I thought was expanding those two sides in other activities and set couple of mature players to handle both, national guards and terrorists. These leaders should be able to give access to everyone that deserves to use the job. I good expanding after that settlement would be making national guards responsible for defending LV turfs and terrorists for conquering them.
Otherwise, the only classical solution is to turn both sides into groups exactly just as SWAT works.
Respond, people. Bring some new thoughts so as to make that feature more useful and entertaining for the new and the old part of the community.