Site Specific: to be - there - or not to be - there?

We have ideals! Such as: a society in which we live and work together in an equal manner. Artists and art educators who work with site-specific research or with community arts gain a lot of information in their projects. What do they learn from working with different people and groups in society? Is any random resident, class or association actually waiting for the arrival of art? What do they bring and what do they leave behind? And what role (s) does the artist actually play in this process?