You know, I've never been able to really appreciate the human drive to collect stuff, even though I'm a collector myself. I do appreciate collections as good conversation-topics, and I would probably go along and see this collection, certainly acknowledge in some way that she's got a funny quirk... but, for me, it wouldn't be about the buttons at all. I'd probably be there to see her boobie-collection.
Alternatively I'd feign an extreme interest and talk about nothing but buttons for the remainder of the night, smoothly evading any and all sexual advances and frustrating her every attempt to back out of the lame joke
that's what she gets for being silly.