Do receptacles installed on a stage (60'flatbed trailer)for a 4 day outdoor event,used to plug in guitar amplifiers and lighting need to be gfi protected?Are receptacles layed out for arts and crafts booths for fans and lighting required to be gfi protected? There is existing wiring already made up from previous years that consist of duplex receptacles,SO cord with 4 square boxes, and raised double duplex receptacle covers, non gfi protected,non weather proof ,layed out on the ground.Event managers want protection as required by code,but also are aware of a light rain shower shutting down the whole event.Are receptacles as stated above considered (in use by personnel)seeing as how the guitar plugs into the amp the amp plugs into the receptacle?