These types usually gather in rural areas where they can shoot and practice their 'maneuvers'. While it is rural areas, they will still not go unobserved. They go to the local grocery store, coffee shops and restaurants, talk to the locals, or may have even be from the local area and know many of the people there and they know them. When they gather, they talk, and they also are pretty good about talking up their political views. When the residents start realizing they are extreme radicals and starting to be up to no good, it doesn't take long to throw up the red flag and get the authorities involved. There are also many times that a current or former member of the group will realize the organization is going rouge (not Palin's way

) in their plans and will contact the authorities and end up working as a mole or informant.
You would be surprised at just how many of these types of groups exist across the U.S. Most of them are basically harmless and have good, although misguided, intentions and will never pose a real threat to anyone. However, the ones that do go overboard must be dealt with swiftly as they are just as dangerous as any other terrorist organization.