I have quite a few pics with some screenwriters I admire. When I worked in film, I attended a lot of premieres and screenings and it's frowned upon to ask for autographs, so I think I have one autographed item (Martin Scorcese on an Oscar poster the year he won for Departed). Favorite person by far is Louis CK, but some other highlights are Guillermo Arriaga, Christopher and Jonathan Nolan, Steve Zaillian, Robert Rodriguez, etc.
I would've been frowned upon, a lot. Would have broken that "no autograph" unspoken rule soooo many times. Lol.