i've never worn road bike shoes - only mountain bike shoes.

I don't have too much of a problem walking around in mountain bike shoes. They suck on tile, linoleum, asphalt, any other man-made flat/hard surface. They're only good off road and on carpets. Mind you, I walk around in my biker shoes regularly at the stores, school, etc. You can't walk fast - that's all.

Oh, also be prepared for people to be looking out for the "person in high heels" when you walk by.