Well, hopefully. I'd also hope she wouldn't take offense. If it had been me you told no thank you, I'd be okay with it because if I were there to write my novel, I'd want to get back to it myself. We all think it's exciting and clever how we come up with our characters, stories, etc. I've been learning it's never as exciting or as clever to others as it is in my own head.

At least not until you become a very popular and well known author. Then, you might be able to get away with it, but primarily because people are there to specifically see you and learn about those things as opposed to wanting to work on their own things in a café. :)