Sorry about your mother. I lost the connnection to martial arts though. Sorry.
I agree that there are bad martial arts instructors around and they teach the gamut of styles and skills including pressure points. I agree that bad martial arts instrustors can be dangerous and I believe this is true regardless of the style or skill set they are teaching.
Beyond that, I started to loose you. Did you go on a bad cruise ship conference on pressure points and Qin-na? I'm unfamiliar with the teaching slogan "You too can learn hidden mysteries to defeat anyone". You must have someone specific in mind.
Who was it? Do you have an instructor you would prefer to endorce? Usually affirming endorcements are more helpful than negative, maybe due to the large numbers of inferior instructors compared to the truly great. Still, if you had such a bad experience, knowing who you are talking about could be helpful in guiding people about what to avoid.
The older I get, the better I was!