In fine dining restaurant do we have to consider a formal attire or proper dress code is a "must" for our diner? Why? Or why not?

formal attire is a must. but if there will be dress code like black color is a must must follow the required code.

YES.WHY BECAUSE FOR THE SEC OF IF THE RESTAURANT SETTING AND FORMAL DRESSING CODE IS NIT THE CUSTOMER IS ENJOY MORE .CONFIDENT FOR THE THING THE CUSTOMER WHO SERVED IN THE RESTAURANTEUR AND THE CUSTOMER IS VERY INTERESTING AND SATISFIED ON THE SERVICE MORE REGARDING TO THE MARKETING THERE IS SOME SLOGANS " FIRST IMPRESSION IS DETERMINATE THE LAST. WE MUST HAVE THE NETT PROFESSIONAL DRESSING

yes we need to dress in a formal attire because a fine dining restaurant is that with a specific dedicated meal and with a very nice decor that attracts people.waiters and waitress dressing formal will add to the beauty of the decor in the restaurant.