I mean basic internet net sense should be more than enough.
Kinda like explaining that you shouldn't step into the alley when the strange man says he has the deal of a lifetime. Anyone who needs to be told not to is going to fall for it no matter how many times they are warned.
That's kinda how these scams tend to work. Like the tech support scam - they actually
want people who have a lick of sense to hang up on them immediately so they don't waste any time/effort on people who were never going to fully fall for it.
So in these kinds of thing, they specifically don't want to waste time on the people who would ask "hang on, why are you sending me a QR code instead of a link?" or "what do you mean
verify
to join your discord server, I'm here ain't I?"