Fred, it depends on what part of that quote that you're specifically referring to. If Mark was condoning the use of "RMS" with reference to power(I don't grasp the full context of the discussion from the quote), then that's imprecise use of language, which generally sets the teeth of EEs on edge, since there is no such thing. A root mean square average is used to calculate the voltage and current which results in an amount of power, but the power itself, i.e., the watt, is a fixed quantity which isn't subject to an average.
If you're referring instead to the manufacturer's rated power spec, as has been pointed out several times here, the FTC regs require that it be measured at the full rated power output for at least five continuous minutes.
