The advantages of belonging to an industrial association lie in its broad perspective, its ability to support members legislatively, and its ability to influence system-wide decisions.
Such organisations act as a comfort zone, voice and back-stop, especially to the disenfranchised. Many also provide member services such as financial, travel and retail bargains.
A clever Principal will not place a 'them and us' divide between associations and the school but rather work closely with members for mutual benefit.
Image courtesy of Michael Leunig