alt Hacker News(Not the parent, but I'm faceblind as well)
The interaction described goes like this:
"Hi there, I'm ABC, nice to meet you, what's your name"
"...Huh? I'm XYZ. We've met before."
"Oh right...sorry, I promise I remember you! We knew each other from there, and we've worked on this and that together, and etc. etc. etc. I'm just terrible with faces, I'm so sorry!"
It's not "you know things about them without recognizing them"; it's "you don't recognize them at first, it gets awkward, and so you recite facts about them prove that you didn't forget who they were"
My aunt said tells neighbors/acquaintances to just introduce themselves by name every time when they start chatting with her, and reports great success with this — but my entire family is also rather 'take it or leave it' re: social stuff, so the people that don't introduce themselves don't get remembered, which seems perfectly fair.