ORIGINAL: Campgems
I believe the basic AMA membership only applies to flying at Chartered fields. Am I wrong??
In this case, yes. The AMA insurance that you carry as an individual doesn't tie you to a particular place, but rather to a standard of conduct. Follow the code of conduct and safety rules, keep your information inside of your airplane, and you're set.
The insurance that the AMA provides to land owners via clubs is contingent upon clubs ensuring that only those bound by the AMA safety code and covered by their AMA membership fly at the site.
The Park Pilot program is an attempt to reach those who might not otherwise have to purchase an AMA membership due to where they fly.