Well here is something you posted in another thread:
From the AMA Club Charter Kit:

"To preserve the availability of low cost insurance to your club and its site owner, the people who fly with your club should contribute their share of that cost. They can do so by becoming dues paying members of your AMA charter club as well. In the same vein, if the landowner for your club’s chartered club field has granted the club exclusive flying privileges, the club should ONLY allow AMA members and current members of the Model Aeronautics Association ofCanada (MAAC) to fly at the field. If your club is flying on public land and it has not been granted exclusive flying rights by the public agency in charge, your club activities should be confined to AMA members, and you are not responsible for other (non-AMA) flier’s actions. Should the public agency be named as an additional insured, it has coverage only for the actions of your club, its members, and other visiting AMA members who are considered guests."

Now, If the land owner does not grant exclusive use to the club then others are allowed...the policy as I understand it covers the land owner for all model flying...members of AMA or not...otherwise a land owner might be at risk from otherwise and unknown model flying use...the policy would be of little comfort unless bullet proof.