Just to be clear, this is directly from the AMA Safety Code:

8) With the exception of events flown under AMA Competition rules, after launch, except for
pilots or helpers being used, no powered model may be flown closer than 25 feet to any
person.

Notice that it does not exclude pilots or their helpers from being closer than 25 feet.

Also, All AMA insurance requires is that you are following the Safety Code. The guidelines for field layout is just that, a guideline. In addition, there is no such thing as an AMA sanctioned field. AMA Charters clubs and sanctions contests, but they do nothing with respect to the flying site beyond giving some general guidelines.