The best description of the AMA coverage, written in plain English, is in the Club Charter Renewal Pakage on the AMA site at
http://www.modelaircraft.org/PDF-files/2005clubkit.pdf . If what you want is the actual liability policy, it, also, is on the AMA site at
http://www.modelaircraft.org/PDF-files/500-l.pdf .
If, after reading those you still have questions, they should be directed to Carl Maroney at AMA headquarters. He is always helpful. One thing though... he does not answer what if questions. I think you can guess why.