If you have a fly in under AMA sanction then you are acting as a club under a set of rules wether you know it or not. You must have a CD and also use a frequency board. If you say you want AMA sanction to get the insurance coverage and then decide to let everyone go his own way then you have just kissed your coverage goodbye. BTW how do you get AMA sanctioned without being AMA members? All this big man bull about not obeying rules is IMHO just plain stupid. If you are flying at a fly in and you are not following all the "rules" I wouldn't want to be in your shoes trying to explain to the judge how your plane accidently disfigured the young girl when it was 'hit'. But hey not to worry their lawyer only wants fifty million. Bottom line. This is a hobby where very expensive lethal projectiles are hurling round a field. Each one of them can suffer any one of a thousand mishaps.
Don't you think there should be some sort of order and safety rules? I take flying large scale R/C planes very very seriously and if you are flying next to me I want you to be just as serious.