I do it! As long as the sole is pretty rigid it's fine. I have one pair of ballet flats that are too soft soled and it hurts to ride in them, but all my other shoes are fine. I find I commute far more often when I don't have to worry about what shoes I can wear. (Well, I don't ride in cowboy boots, because it would look silly and the pedals would really tear up the leather soles.)

Anyway, she is adorable. I am with her on the helmets and other bike gear, though. I don't know why some smart crafty chick isn't making inexpensive panniers with skulls and cherries and martini glasses to appeal to the hipster crowd.