You're welcome, Steve. And thank your for focusing attention on this history through your recording and your posts on this thread.

With regard to your guesses about why very little attention is paid in American schools to the history of slave patrols other than the brief mention that they existed, I believe that it has much more to do with your first guess than with your second.

Furthermore, in my opinion, the fact that the function of slave patrols and their role in maintaining slave codes (and not just in hunting down runaway slaves) is minimized has alot to do with the continued existence in the United States of institutionalized racism.

Here's a definition of "institutionalized racism":

"Those forces, social arrangements, institutions, structures, policies, precedents and systems of social relations that operate to deprive certain racially identified categories equality"
http://dictionary.babylon.com/INSTITUTIONAL_RACISM

As I'm sure that you know, Steve (as a former teacher), in the United States extbook publications are a powerful Eurocentric institution. Most textbooks used in American public schooks don't fully & accurately reflect the history of the United States or the full and accurate history of other nations.

Because of this, persons who really want to learn more about these histories need to do independent research both online and off-line.