I'm not sure if we have good enough systems in place, in terms of UX, for that to work.

Imagine every C-level exec who's opened a top-urgent ticket with IT because their printer doesn't work (they forgot to plug it in/forgot it needs paper/it's not a printer, it's a paper shredder) trying to operate some form of key exchange software securely, while people capable of pulling off this sort of scam are targeting them.

I don't think this is a problem that can be solved with technology.