No it was said to all the leaders in the class on every occasion I've heard it. As far as I'm aware I don't do involuntary shrugs as I receive compression in a Sugar Push.

One instructor who said to use your lats and demonstrated how, clearly didn't know where lats were or how they activate/work. Hence why I'm asking what does engaging my lats actually mean and what's the intended purpose/end of result of doing this.

I got to thinking about it more recently as in lockdown I've been working from home and I've taken the opportunity to workout at home and I bought a pull-up/chin-up bar. I've been using it a lot and the strength of my lats has really improved (pull-ups are hard in your lats 50's).