I found an answer that a biker posted:
“The biker community is a group unto itself and the unwritten laws are obeyed. If you want to form a club or ride with a club that club must be sanctioned by the dominate outlaw group in your area if you cherish your teeth. If your club wants to wear a bottom rocker it must pass the approval of the club in your area, in our case, the Bandidos. The other clubs in our area are support groups such as Los Malos, Guardians and the Mavericks. They actually support the Bandidos, by that I mean that a portion of their dues actually goes to the Bandidos.
The Bandidos don’t exact any dues from patriotic groups such as the Patriot Guard Riders.
http://www.americanponders.com/forum/index.php?topic=9866.50;wap2
Have you seen any Patriot Guard Riders with a bottom rocker?
Technically speaking, PGR isn’t actually a “Motorcycle Club.”