I am sorry, but I call BS on this. What about the requirements for the SE to be a professional? Why are those so easily relaxed because he has a busy day? At a festival, the SEs make more money than any individual performer except for the top two or three headlining acts - they ARE getting paid to be more professional. We should expect that.
Also, there are too many example of excellent SEs I've worked with at festivals that handle all of this stuff with aplomb and make every band sound awesome, and without resorting to a cookie-cutter "each bass rig and drums set sounds exactly the same" approach. With all the examples of SEs who do this right, and make the performers feel comfortable and confident, thus *enabling a good performance*, why do we have to put up with these turd SEs?? There is no reason, no excuse for it. I reject your assertions.