"We teach by example."
Sorry Valmai - not enough for some singers in my experience; those able to respond by example are more often than not, able to handle a basic tune - it's those who can't that raise problems.
Far from 'telling people to 'shut up' as I would never do, preventing singers from humiliating themselves in front of an audience when they are unable even to handle the basics, seems both helpful and humane to me.
I know Frankie and her work well enough to know, (unless she has changed radically) it is aimed at people who can hold tunes.
Anyway - as you say - back to the topic.
Jim Carroll