I'm sorry, but you're wrong. I've worked in concert halls with half-million-dollar sound systems. You don't flip the power on upstream devices (DSPs, boards, etc.) while the amplifiers are powered on.

In nice, modern installs the system integrator will usually have installed a sequencer. You turn a key and what is essentially a glorified rackmount power strip emits a series of clicks as relays on a timer power on sections of the rack in a safe order. Otherwise it is up to the engineer to start up and shut down according to the correct procedure. A mistake will not necessarily damage equipment, but you will hear it pop - which may be anywhere from subtle to deafening. It is a dumb - and not unheard of - way to blow a speaker.

This is becoming less of an issue as digital audio networking (Dante, etc.) takes hold - there may be no analog connections between the mic itself and the amplifier - but it is absolutely standard with analog interconnections.

Why? Because you are amplifying the turn on signal from the source or preamp.

Every time you have ever turned audio equipment on and heard that thump or pop, you are hearing the same phenomenon that ran the risk of damaging headphones left plugged in. It just so happens in most cases the amount of power involved isn't significant, but it does become so once you enter the realm of high powered amplifiers.

There's nothing inherently wrong about a design that doesn't include a muting relay because it is supposed to be understood how the device is operated, in the same way there's nothing inherently wrong about a car design that doesn't lock the gas tank while the car is online and running - you are supposed to know you shouldn't fill up your gas tank while the vehicle is on, and if you do so, there are risks. (Yes, sparks from the engine compartment of running cars can and do cause fires while refueling, albeit rarely)

nwavguy was specifically told to stop advertising in the manner he was, and he didn't. Plenty of other people have gotten the same PM from jude.