I've only declined once, when part of my prop had broken and I was fixing it. The girl was very understanding and waited around until I finished fixing it to take a picture.
[Next Cons]: Holiday Matsuri // Megacon
Mikasa Ackerman - Attack on Titan - 95%
3D Maneuver Gear - 70%
Chiaki Nanami (Super Dangan Ronpa 2) - 0%
Catherine - Catherine - 95% (remaking skirt)