I picked up a new Fluke clamp meter to test out the idea of measuring draw during a show. I used one of those Extec splitters, made for measuring with clamp meters. I was running a PRX XLF sub, PRX 635 3-way cab plus four Chauvet Slim Par Pro LEDS off that circuit. It was a small room so I only had drums and vocals in the PA. With drums slamming (Pop punk) and yelling vocals plus LEDs the meter was showing a steady 2.5 amps.
I understand the meter is not able to show the millisecond transients. I was surprised (but not surprised based on your comments) how low the draw was. I could have run both sides of the PA and lights off than 20-amp circuit.
This explains why, years ago, how we got away with running an entire show off multiple outlets that was really only one circuit.