From the AMA Safety Code:

"6) For Combat, distance between combat engagement line and spectator line will be 500 feet per cubic inch of engine displacement. (Example: .40 engine = 200 feet.); electric motors will be based on equivalent combustion engine size. Additional safety requirements will be per the RC Combat section of the current Competition Regulations."

As it is written, all of the safety rules apply whenever R/C Combat is being flown - regardless of whether it is a large event, or just 2 pilots mixing it up for fun. This includes wearing hardhats and the separation between the spectators, pilots and combat area.

While I agree 100% with the opinions Lou put forth, please be sure to let EVERYONE involved know that AMA coverage could be voided in the very unlikely event of an accident by not following all of the safety rules.

AMA Safety Code:
http://www.modelaircraft.org/templat...-files/105.pdf

HTH,
D