"I would hate for the quality of this website to go down."

I do agree. I come to hacker news just for the reason you listed above;

"meaningful, thought-provoking content."

But HN is also a community. Every now and then for someone to share something like this, I think that's perfectly fine. I do agree if people do take advantage of this, it would significantly reduce the valuable content that I love about HN. We have to trust that his girlfriend really did post this, and didn't pull a fast one on us.

Everything in moderation.