Glorified Scrivener posted:

This isn't an issue I can speak to directly, but several members of my lodge are members of Sigma Chi, alumni and current (I reside in a college town). They don't see a conflict in their dual membership and all of them speak well of their greek experiences.

As for a small clique "controlling" a lodge for an extended period of time; this, like many things masonic, varies from lodge to lodge. The short answer is that yes, it could certainly happen, masonry being after all an organization no less vulnerable to internal politics that any other human enterprise. There are certain aspects of masonic politics on the lodge and grand lodge level that I personally feel are vulnerable to manipulation. Whether or not this is a problem varies from jurisdiction to jurisdiction. Ideally everyone involved takes their obligations seriously and also obeys Wheaton's law, but again, masonry is made up of fallible human beings.

In practice it is typical for the same individuals to be re-elected to multiple terms as treasurer and secretary, as these offices both benefit from an incumbents experience and involve a lot of organizational work that not everyone wishes to volunteer for. Secretaries in particular can accumulate a certain amount of influence over their terms. In lodges with smaller memberships the same individuals do often repeatedly hold the same offices, but if/when membership sees an increase they are usually happy step aside in favor of new blood.

Hope that answers your questions, but note that this is all based on my own personal experiences, others will certainly hold different opinions.